January 20, 2020


In the company of friends...

It seems like the longer I'm in this hobby, the more I learn. And sometimes, the more I learn, the more I realize that what we have been doing for a long time IS not such a bad thing. Yet, sometimes, we as a group tend to forget this stuff.

Yeah, every once in a while, me- Mr. "Question-Everything-You-Know-About-The-Hobby"- will ponder stuff which has long been considered a hard and fast "rule", and beat the shit out of it with my consistent questioning and personal research.

Sometimes, I think I'm correct in my conclusions that we've been too stubborn, and that all sorts of other approaches can not only work- but create better outcomes than we've ever considered!

Other times, I tend to go along with prevailing wisdom, as it really makes no sense to question what seems logical and beneficial for our animals. I still think about it a lot, though. Like, the social structures that we provide when we keep various species of fishes... It something that is fascinating, yet many of us don't give it a lot of thought...We add our fishes to our tanks and simply enjoy them, without much consideration for the fascinating aspects of this stuff! 

That's okay, I guess...but there is a lot to this stuff that I think can really help us enjoy our fishes even more when we study it a bit.

Let me digress for a quick second. Give you a bit of context for what I'm thinking here.

I suppose one of the real fun parts of aquarium keeping is figuring out what fishes you want to keep, and setting up the aquarium to accommodate them. In many cases, not only does "setting up the tank to accommodate them" mean selecting the proper sized tank, environmental parameters, and physical layout, it also means suitable social groups of them.

Now, if you're like me, you love sizable shoals or schools of small fishes-usually characins- in large tanks. There's something about the "scale" and interest that such groups provide, particularly in an aquarium designed to meet their needs. And you, too, have probably have kept many schools of characins and such. You KNOW that most of these fishes simply fail to thrive when not kept in schools.

Schools. Shoals. Groups.

I've always felt that as hobbyists, we need to do all that we can to help facilitate the beneficial aspects of this social behavior.

Oh, but first, a "refresher" of sorts...

The word "fish” is the correct plural form when you’re referring to a group of specimens all belonging to the same species. “Fishes,” on the other hand, refers to a group which consists of more than one species.

Us fish geeks mess that one up all the time.

I mean, I know that I do! 

Oh, and let's just jump on that most confusing of fishy distinctions...the difference between a shoal of fishes and a school of fishes:

A shoal is a group of fish congregating together, perhaps even to benefit from the safety in numbers...yet not moving or behaving in unison. They can be facing in multiple directions, with no coordinated actions.

That's the distinction.

A school is when all of the members of the group are moving and behaving in a coordinated manner. 

Personally, I've always liked the idea of keeping groups of the same species together whenever possible- regardless of if they school together, or simply "cohabit."

And then there are fishes which live in "groups", right?

Social aggregations of fishes which don't really display "coordinated movements" and such, but do exhibit social behaviors in a group setting, such as dominance hierarchies, feeding  and spawning orders, etc.

Okay, all of that grammatical B.S. now safely felt with and tucked away neatly, let's ruminate more about the idea of keeping lots of fish- or fishes- together in our tanks!  I know, it's  sort of "Aquarium Keeping 101", but it's something that we likely tend not to give much thought to as we move on to other stuff, right?

Some of the best fishes to keep as single-species units, in my opinion, are catfishes, like the Corydoras, Brochus, and even the Otocinculus species.

The dynamic of keeping these endearing fish in groups is almost irresistible...and mimics how they are often found in Nature. It's fun to watch, and really enlivens your aquarium experience.

They are really social fish! 

Not only do the fish show their most interesting behaviors in single-species groups, they seem to feed better, stay healthier, and spawn more easily, in my experience.

Makes perfect sense, right?

I recall that I had a sizable group of 14 Corydoras panda a while back in one of my aquariums that lived very well together in a school that I gradually built up. However,  almost paradoxically, they actually seemed to behave more shy- or perhaps you could say, "cautious"-as a large group than they were as individuals or small group.

I would say that they definitely "schooled", but they adapted a strange "schedule" once the group truly became a school, and they were almost nocturnal or crepuscular, often coming out as a school, seemingly from out of nowhere, just as "dusk" broke in my tank (gotta love controllable LED's, huh?)! Of course, if you dropped in food at almost any time of the day, all bets were off, and they came out to feed actively- and then quickly went back to wherever the hell they hid during the day..

And then there are those Otocinculus...

This is a fish that just seems to be, well- problematic- for many...And I think it's no secret that they often suffer from 1) Lack of sufficient algal growth, and 2) The apparent "comfort" of the company of their own kind. They will often live for what seems like extended periods of time in a solitary manner, or even in small groups- only to just sort of "fade" at some point.

Personally, I think that this fish creates a sort of "paradox" for aquarists: One one hand, you want to support it's need for socialization by keeping it in larger groups (say, a minimum of 6-8 specimens), while on the other hand, providing sufficient micro algae growth on rocks, plants, and other aquariums surfaces. I wouldn't even think of keeping this fish in groups of less than 6 individuals...again, possibly problematic if you're tank can't provide sufficient algal growth for them.

Yeah. A paradox.

And of course, everyone knows that some species simply need to be kept in groups to confidently exist in your aquarium. For example, the Glass Catfish, Kryptopterus sp. is a fish that will literally waste away when kept individually, like so many of us probably did with this fish when we were kids. (Okay, well, I did!)

These are fishes that truly have a timid and non-aggressive nature, and they should always be kept in a group...and by "group", I'm thinking 6 or more...even larger, if your tank can accommodate them. And of course, this means an appropriately-sized aquarium and physical layout to accommodate their needs.

(Pic by JohnstonDJ, used under CC BY-S.A. 2.0)

And, if you're curious to see how these fish can act in a large group, check out Tai Strietman's video of his Asian-themed tank. They display a relaxed, gregarious nature, which is much more natural than the skulking-in-the-corner, timid personality they typically display when kept individually. It's plainly obvious, when you watch this video, that these fishes are near-perfect to keep in this fashion, and you'll never attempt keep them individually again! 

You probably have already considered this idea of keeping various species of catfishes in groups, but it's something I felt like touching on because I still see many hobbyists keeping them individually or in very small groups, which is a bit surprising. Now, yes, this is a "general" statement, and it would be irresponsible of me to intimate that it applies automatically to every species. Obviously, there are many exceptions to this.

And of course, there are fishes which tend to be kept singly, which, if the proper space and environment is set up- and if introduced as juveniles together, could sort it out and live in some semblance of a peaceful social order for an indefinite period of time. 

The key there is observation, study, and patience...And the ability to take quick and decisive action should things "head south" in your little aquatic Utopia! 

There is certainly a lot we can learn, and much to consider about the social behavior of our fishes, and how we can provide the optimum conditions to enhance it.

Regardless, in this era where tanks are set up as a" temporary" display, or set up to highlight the aquascape, with the fishes simply being "accessories", we often see tanks with the fishes installed without due consideration for their long-term need. 

It need not be this way. In fact, it shouldn't be this way.

I'd go so far to suggest that, even if you're setting up a temporary display for a competition, or whatever, you need to display them in proper groups. Remember, a display seen by a lot of people who might be influenced by it should be set up with animals in proper context. 

Yeah, it sends the wrong message to the uninitiated to do this.

A simple concept. Probably almost "remedial" in nature. However, something that we need to keep in the front of our mind when setting up our next aquarium, no matter how unique or different it may be. Place the needs of your fishes first. 

You probably know that.

 In fact, I"m certain that you do.

So, please pass along the thought to someone who might not. There are a lot of new people coming into the hobby all the time- and we'd all be better off it they stay in it! 

Stay thoughtful. Stay considerate. Stay supportive. Stay inspirational. Stay devoted. Stay curious...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



January 18, 2020


Little tiny bodies of water...big ideas. Do them...

Confession: I used to hate small aquariums. I really did. I think part of it was because, as a kid, all I could keep in my room ('cause I had like 10 tanks!) was small aquariums. When I was able to get larger tanks, I went all-in on larger tanks (like50-gallons and up) and vowed never to go small again.

My, how times change!

Fast forward a few decades and enter our crazy botanical-style aquarium world here at Tannin, and the idea of using small aquariums is indispensable!

Yeah, I've completely changed my attitude about them, to the point where it's no secret that we love small aquariums around here. For a lot of reasons, really...not the least of which is that they can serve as a sort of reliable and easy-to-iterate "test bed" for lots of new ideas. 

Now, you're also likely aware of the fact that we're crazy about small, shallow bodies of water, right? I mean, almost every fish geek is like "genetically programmed" to find virtually any random body of water irresistible!

Especially little rivulets, pools, creeks, and forest streams. The kinds which have an accumulation of leaves and botanical materials on the bottom. Darker water, submerged branches- all of that stuff...

You know, the kind where you'll find fishes!

Happily, such habitats exist all over the world, leaving us no shortage of inspiring places to attempt to replicate. Like, everywhere you look!

In Africa for example, many of these little streams and pools are home to some of my fave fishes, killifish!

As mentioned above, many of these little jungle streams are really shallow, cutting gently through accumulations of leaves and forest debris.  Many are seasonal. The great killie documenter/collector, Col. Jorgen Scheel, precisely described the water conditions found in their habitat  as "...rather hot, shallow, usually stagnant & probably soft & acid."

Ah-ah! We know this territory pretty well, right?

I think we do...and understanding this type of habitat has lots of implications for creating very cool biotope-inspired aquariums. 

And why not make 'em for killifish?

So, for the most part, these fishes are often found in very shallow jungle streams. How shallow? Well, reports I've seen have stated that they're as shallow as 2 inches (5.08cm). That's really shallow. Seriously shallow! And, quite frankly, I'd call that more of a "rivulet" than a stream!

"Virtually still, with a barely perceptible current..." was one description. That kind of makes my case.

What does that mean for those of us who keep small aquariums?

Well, it gives us some inspiration, huh? Ideas for tanks that attempt to replicate and study these compelling shallow environments...

Now, I don't expect you to set up a tank with a water level that's 2 inches deep..And, although it would be pretty cool, for more of us, perhaps a 3.5"-4" (8.89-10.16cm) of depth is something that can work? Yeah. Totally doable. There are some pretty small commercial aquariums that aren't much deeper than 8" (20.32cm), and you could adapt other containers for this purpose, right? 

We could do this with some of the very interesting South American or Asian habitats, too...Shallow tanks, deep leaf litter, and even some botanicals for good measure.

How about a long, low aquarium, like the ADA "60F", which has dimensions of 24"x12"x7" (60x30x18cm)? You would only fill this tank to a depth of around 5 inches ( 12.7cm) at the most. But you'd use a lot of leaves to cover the bottom...

And another idea for you...Nano brackish tanks!

Here is a pic of my experimental brackish water Epiplatys annulatus setup from several years back. (Yes, there are actually some populations which come from brackish coastal streams! ohhhh!) This one I actually filled to the top, used a fine layer of fine, white sand, and kept the water at a specific gravity of 1.003. It was kind of an odd dichotomy, really, because I used some botanical items in the sort of "island" of rock I created in the lower light area on one side.


You can guess where the fish spent most of their time! I incorporated what I now call "Mariposa Pods" a few little Cariniana Pods, and some Coco Curls into the "island", which had a mix of terrestrial and true aquatic plants, with slightly different water. I guess you could say that it was kind of my first attempt at a "botanical-style brackish water aquarium!" Yeah, it was kind of weird. Not exactly an aquascaping triumph, but an execution on an idea that was in my head for a long time.

(Yeah, I've always liked pushing in different directions!)

You could, of course, do a far more refined version of this early experiment, one with mangroves and leaf litter and a deep, muddy substrate- all of the elements we've talked about, but in a small scale.


Yes, this is another blog where I'm sort of all over the place; must be the caffeine?

The big takeaway here?

Research jungle stream or pool ecology.

Learn which fishes are found in them. Try replicating those super-shallow aquatic environments with nano tanks. Keep the water in the tank really shallow. Add leaves and stuff. Observe. Explore. Enjoy. 

Do this.

Stay creative. Stay excited. Stay curious. Stay observant. Stay informed...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

January 17, 2020


"Environmental impact..."

In recent months, I've spent a lot of time developing some new ideas for botanical-style aquariums; thinking through iterations, processes, materials, and mental shifts that need to be made as we move forward. Some are pretty radical ones. Others, subtle, incremental steps.

All of them are useful and, in my opinion, potentially very interesting!

Among the numerous concepts that I've been thinking about is how specific botanical materials can impact aquatic habitats in the geographical regions from which they come- and how we might be able to take advantage of this in our aquariums.

Of course, it is perfectly logical to imply that botanicals, wood, and other materials which we ultiize in our aquascapes not only have an aesthetic impact, but a consequential physical-chemical impact on the overall aquatic environment, as well.

Not really difficult to grasp, when you think about it in the context of stuff we know and love in other areas of life...

Wine, for example, has "terroir"- the environmental conditions, especially soil and climate, in which grapes are grown, and that give a wine its unique flavor and aroma... And it's well-known that coffee acquires traits from the soils and climates in which it grows that are similar. Tangible effects and characteristics, which impact the experience we get from them.

And of course,  I can't help but wonder if this same idea applies to our botanicals?

It must!

Yeah, it HAS to. Right?

I mean, leaves come from specific trees, imparting not only tannins and humic substances into the water, but likely falling in heavier concentrations, or accumulating in various parts of rain forest streams or inundated forest floors at particular times of the year, or in specific physical locales with in a stream or river.

And, it's absolutely not out of the question to assume that the leaves, seed pods, etc. on these trees and shrubs have different concentrations of these compounds at different times of the year as well, and that these factors have varying influences upon water chemistry, right?

And of course, when these materials end up in waterways, they provide the fishes which reside in that given area a specific set of physical/chemical conditions, which they have adapted to over time. The same with soils and sediments that accumulate on forest floors and meadows (The Pantanal in Brazil comes to mind here), which have an absolute impact on the aquatic environment when the waters return.

Is this not the very definition of "terroir?"

Yeah, sort of...right? 

Actually, it makes perfect sense.

As we've discussed before, the soils, plants, and surrounding geography of an aquatic habitat play an important and intricate role in the composition of the aquatic environment. They influence not only the chemical characteristics of the water (like pH, TDS, alkalinity), but the color (yeah- tannins!), turbidity, and other characteristics, like the water flow. Large concentrations of botanical materials or leaves become physical structures in the course of a stream or river that affect the course of the water.

And of course, they also have important impact on the diet of fishes...Remember allochthonous input form the land surrounding aquatic habitats? And the impact of humic substances? Yeah, these factors are extremely important in the grand scheme of things.

And of course, I simply can't help but wonder what sorts of specific environmental variations we can create in our aquarium habitats; that is to say, "variations" of the chemical composition of the water in our aquarium habitats- by employing various different types and combinations of botanicals and aquatic soils.

I mean, on the surface, this is hardly a revolutionary idea...

We've been doing stuff like this in the hobby for a while- more crudely in the fish-breeding realm (adding peat to water, for example...), or with aragonite substrates in Africa Rift Lake cichlid tanks, or with mineral additions to shrimp habitats, etc.

Now, this is NOT exactly the same idea as the "biotope aquarium" crowd plays with, IMHO. That's more of a physical and arguably "superficial" attempt at replicating aspects of the natural habitats from which our fishes hail. Very, very cool- but different, I believe, than what we're talking about here.

We can, of course, borrow "mental capital" from the work done in other aquatic endeavours. It's there for the taking, lol.

In the planted aquarium world, for example, it's long been known that soil types/additives, ie;  clay-based aquatic soils, for example, will obviously impact the water chemistry of the aquarium far differently than say, iron-based soils, and thusly, their effect on the plants, fishes, and, as a perhaps unintended) side consequence, the overall aquatic environment will differ significantly as a result.

So, it pretty much goes without saying that the idea that utilizing different types of botanical materials in the aquarium can likely yield different effects on the water chemistry, and thus impact the lives of the fishes and plants that reside there- is not that big of a "stretch", right?

It isn't.

I can't help but wonder what the possible impacts of different leaves, or possibly even seed pods from different areas can have on the water and overall aquarium environment.

I mean, sure, pH and such are affected in certain circumstances - but what about the compounds and substances we don't- or simply can't- test for in the aquarium?  What impacts do they have? Subtle things, like combinations of various amino acids, antioxidant compounds, obscure trace elements- even hormones, for that matter...

Could utilizing different combinations of botanicals in aquariums potentially yield different tangible results for our fishes? You know- scenarios like, "Add this if you want fishes to color up. Add a combination of THIS if you want the fishes to commence spawning behavior", etc.

It sounds a bit exotic, but is it really all that far-fetched an idea?

Absolutely not, IMHO.

I think the main thing which keeps the idea from really developing more in the hobby- knowing exactly how much of what to add to our tanks, specifically to achieve "x" effect- is that we simply don't have the means to test for many of the compounds which may affect the aquarium habitat.

At this point, it's really as much of an "art" as it is a "science", and more superficial observation- at least in our aquariums- is probably almost ("almost...") as useful as laboratory testing is in the wild. Sure, we can test for tannins in the aquairum- but what does it mean? What is a concentration that makes sense for our purposes? What's a "good" number? Is there any correlating test work on these substances being done in the wild aquatic habitats?

Now, I have found some work on ionic and trace element concentrations in some well-known aquatic habitats, but the ability for a hobbyist to test for many of the compounds measured is virtually non-existent at the present time. I can only hope that at some point, detailed hobbyist-level ICP-OES analysis- similar to what is available for reef tanks, becomes available for freshwater hobbyists. That would be a game-changer!

At least at the present time, we're largely limited to making "superficial" observations about stuff like the color a specific botanical can impart into the water, etc. Impact on pH, TDS, etc. is what we have to work with- better than nothing, I suppose! Of course, our home aquarium "field studies" of our fishes in various water chemistry scenarios is useful for our purposes! Even simply observing the effects upon our fishes caused by environmental changes, etc. is useful to some extent.


Of course, not everything we can gain from this is superficial...some botanical materials that we play with actually do have scientifically-confirmed impacts on the aquarium environment; or on fish health, at the very least.

In the case of catappa leaves, for example, we can at least infer that there are some substances (flavonoids, like kaempferol and quercetin, a number of tannins, like punicalin and punicalagin, as well as a suite of saponins and phytosterols) imparted into the water from the leaves- which do have scientifically documented affects on fish health and vitality. 

When we first started Tannin, I came up with the term "habitat enrichment" to describe the way various botanicals can impact the aquarium environment. I mused on the idea a lot. (I know that doesn't surprise many of you, lol...) Now, I freely admit that this term may be interpreted as much a form of "marketing hyperbole" as it is a useful description.

However, I believe that the idea sort of resonates, when we think of the aquarium as an analog for the wild aquatic habitats, and how the surrounding environment- the terroir- impacts the aquatic environment, right?

As we play more and more with the "Urban Igapo" idea of creating a "wet-dry" seasonal cycle replication in aquariums, perhaps this dynamic can be more easily and dramatically understood by hobbyists.

And of course, when it comes to utilizing botanicals and creating more "authentic" blackwater conditions in our aquariums, we hear the interesting stories from fellow hobbyists about dramatic color changes, positive behavioral changes,  rehabilitated fishes, and those "spontaneous" spawning events, which seem to occur after a few weeks of utilizing various botanicals in aquariums which formerly did not employ them.

Sure, these are not carefully-controlled scientific experiments. Likely, a good number of these interesting events and effects could likely be written off as mere coincidences or anecdotal occurrences. However, when it happens over and over and over again in this context, I think it at least warrants some consideration! There must be "something in the water", right?

We're slowly figuring this stuff out.

Yeah, we’re artists at this point. 

And this stuff is really as much of an “art” as it is a “science”, IMHO. 

There is so much we don’t know yet. Or, more specifically, so much we don’t know about botanicals in the context of keeping fishes. We're still largely in an "experimental" phase, and likely will be for some years to come. And that's just fine with me...The "art" is pretty fun and engaging at this point!

We need to tie a bunch of loose ends together to get a really good read on this stuff until we get to the "Dial-a-River” additive stage ("Just add a little of this and a bit of that, and...")

But we're slowly getting there...At least in terms of understanding some of the tangible benefits of botanical use, besides just the aesthetics.

Continued experimentation with different approaches within our botanical-style aquarium obsession is likely to yield more information that will advance the "state of the art." Allowing ourselves to "get out of our own way" and give serious thought to the impacts of things like alternative substrates, and "substrate-centric" aquariums is a really huge avenue for us to explore. We're literally just scratching the surface here.

And it all starts with understanding the impact of...the terroir, right? The impact of the materials that we use on the aquatic environments of our fishes. It's something we've played with for years, but are only recently starting to understand...Separating mere aesthetics from a deeper, possibly more meaningful understanding of Nature as it relates to our aquariums.

Stay observant. Stay resourceful. Stay methodical. Stay curious. Stay dedicated.  Stay creative...

And Stay Wet.


Scott Fellman

Tannin Aquatics 




January 16, 2020


No magic elixir...

As more and more hobbyists start incorporating botanical materials in all sorts of aquariums, we are once again exposed to a lot of different approaches, ideas, and "techniques."

There is a sort of "blending" of approaches and techniques- all of which serve to bring us joy and appreciation for the wonders of Nature. However, we often tend to "edit" Nature, polishing out or trying to "bypass" the processes, aesthetics, and functions that we find distasteful- in search of what we have generically called a "balanced" aquarium.

It's a noble, important goal. However, I think we need to understand that Nature seeks "balance" in Her own way- one that really doesn't take into account our schedules, goals, or aesthetic preferences.

And it's well known that an aquarium is a closed ecosystem that can easily "fall out of balance."  

We often say it's "delicate"- but I don't think that it is. Rather, it's a robust system, which establishes itself in a way that utilizes "what's available" at any given time. And sometimes, it results in the pendulum shifting from one life form to another. The "balance" may be delicate; in that various life forms can "take over" at any given time- and rapidly, too.  However, if you've ever battled something like an algae bloom- you'd never call the life forms themselves "delicate", right?

They're tenacious. You have to respect that. Any life form that takes advantage of optimum conditions to thrive is at least worthy of some appreciation- even if it looks like- well- shit, right?

Sure. excessive algae growth is a sign of imbalance of something- light, nutrients, often exacerbated by deficiencies in husbandry, or a combination of these factors. This is  "Aquarium Keeping 101", of course, but when you're in the middle of these kinds of struggles, it's easy to overlook seemingly "basic" stuff.

It is not always easy or clear to understand why a tank is "out of balance." Sometimes, it just takes time to figure it out. I think the important thing is to think of an aquarium- especially our botanical-style aquariums- as a small, closed ecosystem or microcosm, with internal and external influences-any one of which  may be extremely impactful when they converge.

Understanding that the various possible impacts that our techniques and executions may have on our aquariums is just the start. On the most superficial level, adding a lot of botanical material into a tank is a recipe for: a) a lot of bioload for resident organisms to process, b) a substrate for biofilm and/or algal growth, and c) biodiversity- a proliferation of a variety of organisms.

And of course, "bioload" can be taken advantage of by a particularly adaptable life form which could proliferate more quickly than others...throwing your little ecosystem "out of balance." 

This is part of the reason why the so-called "Walstad Method" for planted aquariums, which I love dearly, proffers incorporating fast-growing plants from the start..They will compete with algae for the same nutrients, and typically, they'll out-pace the algae as they grow.

It's about starting out your aquarium to empower various life forms to help seek a balance.

In our "Urban Igapo" approach, we advocate what amounts to a "dirted bottom" aquarium, sans aquatic plants (at least, initially) and a "sand cap" over the soil. Rather, we plant terrestrial plants and/or grasses (ideally, submersion-tolerant ones) during the "dry" phase. And of course, when we add water, the abundance of nutrients in the substrate creates a significant "bioload" in the now aquatic environment.

"Stuff" is going to happen.

Perhaps- do we dare say, the UI is the metaphorical "ugly stepchild" of the "Walstad Method?" Maybe, but I suppose that could be viewed as a bit presumptuous. 

Ceding a lot of the control to Nature is hard for some to quantify as a "technique" or "method", so I get it. At various phases in the process, our "best practice" might be to simply observe...

And with plant growth slowing down, or even going completely dormant while submerged, the utilization of nutrients via their growth diminishes, and aquatic life forms (biofilms, algae, aquatic plants, and various bacteria, microorganisms, and microcrustaceans) take over. There is obviously an initial "lag time" when this transitional phase occurs- a time when there is the greatest opportunity for one life form or another (algae, bacterial biofilms, etc.) to become the dominant "player" in the microcosm.

It's exactly what happens in Nature during this period, right?

In our aquarium practice, it's the time when you think about the impact of technique-such as water exchanges, addition of aquatic plants, adding fishes, reducing light intensity and photoperiod, etc. and (again) observation to keep things in balance- at least as much as possible. You'll question yourself...and wonder if you should intervene- and how..


Someone in the system- one life form or another-will exploit the available resources, to the detriment of others, and the key here is observation, followed by intervention as needed/desired. "Intervention" being manipulation of environmental parameters or impacts in order to "rebalance" the ecosystem- if you can,or if you feel you must.

Like in any aquarium, there is no "magic elixir"- no single solution to a situation like this.

It's about a number of measured moves, any of which could have significant impact- even "take over" the system- if allowed to do so. This is part of the reason why we don't currently recommend playing with the UI on a large-tank scale just yet. (that, and the fact that we're not going to be geared up to produce thousands of pounds of the various substrates just yet! 😆)

Until you make those mental shifts to accept all of this stuff in one of these small tanks, the idea of replicating this in 40-50, or 100 gallons is something that you may want to hold off on for just a bit.

Or not.

I mean, if you understand and accept the processes, functions, and aesthetics of this stuff, maybe you would want to "go big" on your first attempt. However, I think you need to try it on a "nano scale" first, to really "acclimate" to the idea.

The idea of accepting Nature as it is makes you extremely humble, because there is a realization at some point that you're more of an "interested observer" than an "active participant." It's a dance. One which we may only have so much control- or even understanding of! That's part of the charm, IMHO.

These habitats are a remarkable "mix" of terrestrial and aquatic elements, processes, and cycles. There is a lot going on. It's not just, "Okay, the water is here- now it's a stream!"

Nope. A lot of stuff to consider.

In fact, one of the arguments one could make about these "Urban Igapo" systems is that you may not want to aggressively intervene during the transition, because there is so much going on! Rather, you may simply want to observe and study the processes and results which occur during this phase. Personally, I've noticed that the "wet season" changes in my UI tanks generally happen slowly, but you will definitely notice them as they occur. 

After you've run through two or three complete "seasonal transition cycles" in your "Urban Igapo", you'll either hate the shit out of the idea- or you'll fall completely in love with it, and want to do more and more work in this alluring little sub-sector of the botanical-style aquarium world.

The opportunity to learn more about the unique nuances which occur during the transition from a terrestrial to an aquatic habitat is irresistible to me. Of course, I'm willing to accept all of the stuff with a very open mind. Typically, it results in a fascinating, utterly beautiful, and surprisingly realistic representation of what happens in Nature.

It's also entirely possible to have your "Urban Igapo" turn into an "Urban Algae Farm" if things get out of balance. Yet, it can "recover" from this. Again, even the fact that a system is "out of balance" doesn't mean that it's a failure. After all, the algae is thriving, right? That's a success. Life forms have adapted. A cause to celebrate.

It happens in Nature, too!

I know, seems weird. What we've long feared- what we've always felt looked like "failure"- is actually something to cherish. A huge, HUGE "mental shift" that literally goes against every single thing you've been taught in the hobby.

Scared yet?

I can see why you would be.

We're essentially asking you to do the equivalent of turning a potted plant into a fish pond. And that's sort of- well, sort of crazy, right? Well, maybe not. I mean, this transition has been happening in the igapo- the flooded forests- of South America for eons. Nature has processes, organisms and parameters which allow this annual transition to occur. Life forms have adapted to this cycle. 

Now, sure, the forests of South America are open ecological systems, and your 2-gallon "Urban Igapo" in suburban Cincinnati isn't...On the other hand, the same processes and laws which govern the functions of the forest impact the function in your little experimental glass box. 

Once again, the idea of a "mental shift" to accept and understand the processes and the way they look and impact our closed systems is a huge part of the equation. Think about this: Yeah, the tank may look like a cloudy, brown, glass full of shit at some phases of the terrestrial-aquatic transition. However, there are reasons why, right? Nature is trying to establish a functioning little ecosystem, and not all of this fits our definition of "attractive." 

But it's "natural."

And what's wrong with it? The looks? I mean, are your fishes dying? No? Than what's the real "problem" here?

Yeah, I know, it's a weird way of thinking of this.

If you make this kind of "mental shift", you'd even be ablel to tolerate, accept, and even appreciate the appearance of biofilms, "beard algae", fungal growth, and any number of things that you'd likely see during this environmental transition. It's simply Nature working through her transitional process.

Yet, accepting all of this stuff-aesthetic and otherwise- is contradictory to what we've been taught over generations to be "acceptable" in an aquarium. However, if you really want to own a  real "Nature Aquarium" (sic), then I think that you need to make this big "mental shift." 

This is what Nature looks like.

And there is no single thing that you can do, change, or add to magically transform your "Urban Igapo" into a shiny-clean, perfectly-balanced closed ecosystem. No "magic elixir" or single practice to get you perfectly predictable results every time.

Rather, its a series of changes, practices, processes, and the passage of time, which we as hobbyists need to study, understand, and accept. The whole idea of the UI is to foster a closed ecosystem- to replicate, on a small scale- what happens in Nature. It starts by accepting what happens in Nature, and letting it play out in our aquariums.

Nature finds a way. Nature knows how to do this.

It's up to us to decide wether to understand and accept- or to resist and circumvent the offerings of Nature.

Which way will you go?


Stay determined. Stay curious. Stay observant. Stay patient. Stay resourceful. Stay open-minded...

And Stay Wet


Scott Fellman

Tannin Aquatics 

January 15, 2020


The "dynamic botanical substrate": Nature unleashed.

Once again, my fascination with aquarium substrates is taking us down to the bottom today! I'm obsessed with the idea of "functionally aesthetic" substrates in our botanical-style aquariums. 

It's because I imagine the substrate as this magical place which fuels all sorts of processes within our aquariums, and that Nature tends to it in the most effective and judicious manner. 

Yeah, I'm a bit of a "substrate romantic", I suppose.😆

I think a lot of this comes from my long experience with reef aquariums, and the so-called "deep sand beds" that were quite popular in the early 2000's.

A deep sand bed is (just like it sounds) a layer of fine sand on the bottom of the aquarium, intended to grow bacteria in the deepest layers, which convert nitrate or nitrite to nitrogen gas. This process is generically called "denitrification", and it's one of the benefits of having an undisturbed layer of substrate on the bottom of the aquarium.

Fine sand and sediment is a perfect "media" upon which to culture these bacteria, with its abundant surface area. Now, the deep sand bed also serves as a location within the aquarium to process and export dissolved nutrients, sequester detritus (our old friend), and convert fish poop and uneaten food into a "format" that is usable by many different life forms.

In short, a healthy, undisturbed  sandbed is a nutrient processing center, a supplemental food production locale, and a microhabitat for aquatic organisms. 

You probably already know most of this stuff, especially if you've kept a reef tank before. And of course, there are reefers who absolutely vilify sandbeds, because they feel that they "compete" with corals, and ultimately can "leach" out the unwanted organics that they sequester, back into the aquarium. I personally disagree with that whole thing, but that's another battle for another time and place! 

Okay, saltwater diversion aside, the concept of a deep substrate layer in a botanical-style aquarium continues to fascinate me. I think that the benefits for our systems are analogous to those occurring in reef tanks- and of course, in Nature. In my opinion, an undisturbed deep substrate layer in the botanical-style aquarium, consisting of all sorts of materials, from sand/sediments to leaves to twigs and broken-up pieces of botanicals, can foster all sorts of support functions.

I've always been a fan of in my aquarium keeping work of allowing Nature to take its course in some things, as you know. And this is a philosophy which plays right into my love of dynamic aquarium substrates. If left to their own devices, they function in an efficient, almost predictable manner.

Nature has this "thing" about finding a way to work in all sorts of situations.

And, I have this "thing" about not wanting to mess with stuff once it's up and running smoothly... Like, I will engage in regular maintenance (ie; water exchanges, etc.), but I avoid any heavy "tweaks" as a matter of practice. In particular, I tend not to disturb the substrate in my aquariums. A lot of stuff is going on down there...

Amazing stuff.

Even in "non-planted" aquariums, playing with this stuff opens up a whole new area of aquarium "exploration."

Like any dynamic habitat, the "botanical-style substrate" relies on a variety of organisms to do the job of processing nutrients. A healthy and diverse assemblage of organisms dwelling in this layer, ranging from bacteria to fungi too worms and small crustaceans comprise what we call the "infauna." Essentially, the infauna is a collective of organisms which do most of the work in keeping a botanical-style aquarium functional and healthy.

These small organisms  do a LOT!  

They will consume excess food, process detritus, and even some algae. During this process, they digest and excrete some of this stuff as waste. In turn, bacteria process the "waste", which keeps the whole  infauna community- and the biological "filtration" of the aquarium- functioning.  

As you know, I've long had a sort of affection for detritus. It's simply not a problem IMHO- particularly in the context of a deep substrate bed. Most of this stuff will be processed by the resident infauna, and consumed by resident fishes.

We talk about the concept of "substrate enhancement" or "enrichment" a lot in the context of botanicals (we tend to use the two terms interchangeably). They're not particularly scientific, yet I think that the monikers work well. We're not talking about "enrichment" in the same context as say, planted aquarium people, with nutritive materials (vitamins, minerals, fertilizers, etc.) put into the substrate specifically for the benefit of plants.

Rather, "enrichment" in our context refers to the addition of botanical materials for creating a more natural-appearing, natural-functioning substrate- one which provides a suitable haven for microbial life, as well as for fungi, small crustaceans, biofilms, and even algae, to serve as a foraging area for our fishes and invertebrates. There is something oddly compelling to me when I look at both aquariums and natural biotopes with a diverse, interesting bottom structure.

They are diverse harbors of life, ranging from fungal and biofilm mats, to algae, to epiphytic plants. Decomposing leaves, seed pods, and tree branches compose the substrate for a complex web of life which helps the fishes we're so fascinated by to flourish. And, if you look at them objectively and carefully, they are beautiful.

Detritus ("Mulm") located in the sediments is the major source of energy and/or nutrients for this dynamic habitat. The bacteria which perform all the important chemical reactions, such as converting ammonia to nitrite, nitrates to nitrogen, releasing bound-up nutrients, neutralizing hydrogen sulfide, etc. will obtain  essential nutrients from the detritus (this is what autotrophic bacteria that metabolize ammonia/ammonium or hydrogen sulfide for energy do).

These bacteria may also "harvest" those nutrients, as well as metabolize (aerobically or anaerobically) the organic compounds present in the detritus for energy, just like heterotrophs do.

The processing of nutrients in the aquarium is a fascinating one; a real "partnership" between a wide variety of aquatic organisms.

Yes, there is a lot of amazing biological function occurring in these layers. Now, hobbyists have played with deep sand beds in aquariums for many years, and knowledgable proponents of natural aquarium management, such as Diane Walstad, have discussed the merits of such features in far more detail, and with a competency that I could only dream of! That being said, I think the time has never been better to experiment with this stuff!

Again, we're talking about utilizing a wider variety of materials than just sand, so the dynamics are quite different, offering unique functions, processes, and potential benefits.

I'm fascinated by the different types of soils or substrate materials which occur in blackwater systems, and how they influence the aquatic environment. Keep in mind that many of the habitats we obsess over, like Amazonian "igapos" and "igarapes" are seasonally-inundated forest-floor features, so it goes without saying that the terrestrial soil composition and associated biomass have significant influence on the aquatic environments that emerge during the wet season.

Yeah, we know a little about that stuff, right?

So, the idea of a "dynamic substrate", comprised of a variety of materials, will create a very efficient functionally aesthetic habitat for a variety of life forms. Higher organisms such as "Blackworms", "Trumpet Snails", Planarians (not the nasty parasitic ones), GammarusDaphnia, etc. will compliment the bacteria, fungi, and other life forms which live in sediments and sand.

And I should once again point out that my vision of a "dynamic "botanical-style substrate is one comprised of materials like leaves and bits of botanicals mixed in with, on top of, or in place of traditional sand. My obsession with botanical materials to influence and accent the aquarium habitat caused me to look at the use of certain materials that are reminiscent of those found in the wild aquatic habitats, to augment the more "traditional" sands and other substrates used in aquariums. 

And in some instances, as mentioned above-to replace them entirely.  

We have sourced materials which we feel recreate some of the appearance, texture, and function of the tropical streams and rivers that we obsess over. Some, like "Fundo Tropical" and "Substrato Fino" are coconut-derived, and will not only "tint" the water, but will impart those humic substances and such that seem to be so beneficial for many fishes. And then we have our more "leaf-centric" materials, such as Mixed Leaf Media and "MLM2", which provide a different look and function.

We are getting ready to release several more botanical materials that we think will be perfect for this purpose, so stay tuned. 

The texture of these types of materials tends to facilitate the growth of small life forms, like  bacteria and higher organisms (like worms, creatures like Gammarus, and other crustaceans) can thrive and reproduce, processing uneaten food and other materials, which providing the occasional "snack" for foraging fishes. 

Obviously, we're not advocating just recklessly throwing "stuff" into your tank and waiting for something good to happen. I suppose the "con"side of incorporating these types of materials would be that you could overdo it, at least at the outset. You know, adding too much too soon, possibly overwhelming the resident bacteria population in an established aquarium, potentially rapidly reducing pH or even oxygen with excess enthusiasm! It's possible- perils that are well-known to most in our community.

Of course, with this type of experimentation, we need to employ a healthy dose of common sense and good habits. It's important to have adequate water movement, creation, and overall good husbandry when attempting such a substrate.

Well, yeah.

This kind of combination of natural materials can create a potentially messy substrate area if you are not a careful feeder, over-stock your aquarium, and tend to let things go. So, just be conscientious about maintenance! Makes sense, right?

Working with ideas like this always requires that we proceed slowly and cautiously- looking at the potential for issues as thoughtfully as we do at the opportunity to do "evolutionary" things. Building a botanical-style aquarium system is not simply about a different "look."

It's about creating a biological system optimized for the blackwater environment. With a substrate comprised of botanical materials which specifically compliment the overall aquarium habitat, the possibilities for success with these unique systems are significant!

It will require some responsible experimentation, patience, observation, reflection- and occasionally failure. Personally, I have not had any disasters with my years of experimenting with botanical-style substrates and sediments/sands. That doesn't mean that you'll be immune to problems. It just means that if I can pull it off- you certainly can, too. The "learning curve" with this type of stuff is likely a bit unpredictable, but I think it's well worth taking on!

We're literally just "scratching the surface" of the idea of dynamic botanical substrates, and the next set of insights, discoveries, and even breakthroughs- is out there for the taking.

Let's get after this!

Stay brave. Stay curious. Stay open-minded. Stay innovative. Stay resourceful. Stay observant. Stay patient...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


January 14, 2020


Shortcuts, "hacks" and processes...

Not too long ago, I was "talking shop" with a fellow aquarium hobbyist/vendor, who runs a company in a different "sector" of the industry. We talked about our businesses, the challenges, the customers, and the hobby in general. Around mid-point in the discussion, there was a strange pause. Why? Well, both of us were totally blown away by an enormous hunger for seemingly basic hobby information.

Checking back through the many emails, DMs, and other messages I've received over just the past few months was quite remarkable!  I mean, the amount of questions we field on stuff that would be considered “primary” aquarium-keeping technique was overwhelmingly disproportionate to more advanced topics discussed on our social media, here in "The Tint", and during presentations at clubs. 

Sure, as a hobby vendor, especially one who puts out a fair amount of content like I do, you're alternatively a friend, teacher, therapist, mentor, and always a fellow fish geek. It goes with the territory, and I love it. 

Like, to say that I was surprised was an understatement. Sure, the questions about botanical-style aquarium stuff was a little more "focused", and there were quite a few really cool, esoteric, biotope and process-related queries- but the underlying questions of the vast majority of the them were focused on things like the nitrogen cycle, managing bioload, and what I call "remedial" questions about pH/hardness, stocking, and suitability of various materials for aquarium use.

Now, I like to say that there's no such thing as a stupid question. However, there is such a thing as a "fundamental question"- one which, although "wrapped" in a more advanced or arcane topic (like, botanical-style, blackwater aquariums), is essentially a question about a basic "tenant" of aquarium-keeping that should have been understood from day one in the hobby- long before the reader stumbled on us!

Yeah, it's sort of strange.

I mean, on one hand, you're happy to have people engaged and interested in the stuff we talk about here. However, on the other hand, you're often scratching your head, wondering why more hobbyists seem to lack an understanding of some of the most basic hobby concepts. 

We talked about this concept for a long time, and tried to get our heads around it all. Why would this be? Why do so many hobbyists seem to lack an understanding of the basics? I sometimes wonder if the root cause is that there is just too much "distraction" lying just past the "entry level" to the hobby.


I mean, we’re in what I like to call the “Postmodern” era of aquarium keeping, where hobbyists are trying all sorts of advanced techniques and technology, and sharing rapidly via the internet. Everyone is an Instagram "influencer" or "brand evangelist" these days.  And man, if you have a YouTube channel, you're instantly branded as a (gulp) "expert" by the masses.

Today's hobbyist is far different than the hobbyist of only a couple of decades ago, for many reasons. Aquatic hobbyists spend a collective fortune on the latest and greatest equipment: lighting technology, controllers, filters, pumps, etc. We are bombarded with lots of data on husbandry, animal care, setting up systems, etc. Advanced hobbyists- true "experts"- easily interact with outright beginners, thanks to the power of the internet.

Gadgets and other products promising to leapfrog you to success with minimal struggle are an iPad tap away.

Information is everywhere. 

Well, maybe the information is everywhere, but I get this sneaking feeling that many hobbyists are not taking advantage of all of it.

I saw this in the reef aquarium world near daily: Why would reefers who have 200-gallon plus systems, with thousands of dollars in livestock and equipment  be completely struggling, and have super-specific, detailed questions- and dramatic misconceptions about really basic shit like the nitrogen cycle, alkalinity, water quality, and stocking? Stuff that they should have acquired as fledgling hobbyists, or during their planning phases in the hobby adventure.

We're literally bombarded with shortcuts and hacks, and little emphasis is given to the far less sexy natural processes which control what happens in aquatic ecosystems.

How could this be?

Put a tack in that. We'll come back to it.

Another observation that I have is a sort os strange "misappropriation", or perhaps, a "disconnect" that many hobbyists seem to have about Nature and its processes (all of which influence what happens in our own aquariums). It seems that the cool "visuals" of beautiful aquariums online have given many an "exemption" from having to understand what goes on in the wild, and how it can influence their home aquariums.

It shouldn't be this way. 

This is at least part of the reason why we at Tannin have invested so much time, energy, and money in sharing inspiring and (hopefully) interesting information about the wild tropical aquatic habitats of the year, and how their form and function can be incorporated into our aquariums. Oh, and how we can protect them from environmental threats... That's kind of important, right?


If we can't grasp what goes on here....

...then we'll never grasp what's going on in HERE!

Okay, I think we've identified some of the key issues here. Time for a little more analysis and ideas for how to fix them. And, well, I have a couple of thoughts and theories about why (Well, of course I do, right?)...

The Internet has changed everything

“Okay, Fellman, sure- go ahead and blame the ‘net. Slap Twitter, YouTube or Instagram again while you’re at it…” 

The low hanging fruit? Well, perhaops- but..hear me out on this. I think that the internet and all of the information access it provides has been culture changing. It's amazing. However, some of the change in our hobby may not be for the better. It sort of exploits the less attractive parts of the human psyche, like impatience and desire.

There was a time when a beginner in the hobby went down to the LFS, had a conversation with the staff about starting a tank, and was sent home with some information and perhaps even cracked a book or two…BEFORE he or she even bought a tank. It took some time, a bit of effort, and required us to take a tiny amount of initiative. And it took a lot of patience.

With the internet, all of this information that you had to go out to obtain is readily available on your phone or laptop, along with forums where a fledgling hobbyist can discuss the hobby with experienced veterans.  You don't even have to leave your couch. This is amazing!

All this stuff...right at your fingertips! That's great. I love it.

However, there are also hundreds of “build threads”, advertisements, and online vendors (just like mine) dangling all sorts of goodies in front of the neophyte. "Lessons" that seem to show flashy results, with little discussion of the underlying "boring" stuff (like, you know  the nitrogen cycle; shit like that...). You can just MOVE! 

For just a few dollars  you can have all of this cool stuff delivered overnight right to your door! If you do it "right", and if you can afford it, you’ll be able to go from thinking about starting an aquarium to a full-fledged, high-octane system with all of the latest expensive gear and livestock by next weekend!

So, maybe part of this is a cultural shift brought about by the era of e-commerce. Things are just easier now. Again, this is not "bad"- it's just indicative of where we are as a society.

We have become accustomed to wanting something and getting it…fast. Why research the underlying processes which control what happens in your tank? I mean, there are products and equipment available that can give you “professional results” with virtually "plug and play setup."

You can bypass all of that boring nonsense, like understanding the nitrogen cycle, or the concept of water quality management. We have live bacteria in a bottle, and electronic controllers to just set things up for us.


Perhaps even too easy?

Have we simply decided, in this fast-paced era, to just bypass the “learning curve?” Are we as a culture (and as businesses) so eager to get new hobbyists into our "purchasing funnels" that we are enabling them to bypass the “dues paying” part of the climb to hobby success? Should there be a “dues paying” time, anyways? It's a valid question, although a bit harsh, I suppose.

Who has the right to dictate THAT? Besides, why do you need to "pay dues?"

On the other hand, are we exposing hobbyists to financial ruin, and most important- hapless animals to death because the newbie wants the rare cichlid or deepwater Acropora and “should” be able to keep it because of her crazy filter, fancy additives, protein skimmer, controllable LED lighting, DC water pumps, and a capable electronic controller monitoring the whole thing can help?

This dovetails nicely with my next theory:

Why bother to go the the effort to fully understand the physiological and environmental aspects of what the plants and fishes need? The equipment will take care of it, right? Besides, we don't have the time...right?

You could carry this "logic" to the "nth degree" and look at larger "cultural shifts", right?  I mean, there are parallels here. We could argue that we've gotten to the point where no one wants to brew a cup of coffee anymore. We have the “K-Cup” to do that. I laugh every time I see those commercials for "meal kits" on TV.  You know, 'cause it's easier to open a few packs, heat the stuff up, and you're done. Instead of going to the refrigerator, gathering the ingredients, heating them up, and...

Maybe we’re too busy?

Oh, wait- I get it. The idea is that these things get you the "finished product" without the underlying tedium or learning the processes/techniques involved to get them.

We're too busy...Yet, we will spend a fortune fixing the problems brought on by some of these "advances" and the gaps they've left in our knowledge of the hobby. Or worse- we'll just quit?

Think I’m overreacting?

I don’t think so. I’ve been approached as a vendor numerous times to give “remedial reef keeping” lessons to people who have obscene amounts of money invested in reefs that would put mine to shame, equipment-wise. Problem was, they hadn’t a clue about keeping the animals they built their technological shrines for. I know many fellow vendors and LFS people have had the same experiences.

Have we as a hobby and industry made the process of actually understanding the life forms that we keep secondary to simply acquiring them? Makes me shudder a bit.

And I'm not trying to take the "You guys have it so easy- I had to walk to school through 6 feet of snow..." mentality. It's not about, "Newbies have to pay their dues! They don't have the RIGHT to success.."


The point is- we owe it to our animals- and ourselves, to understand this stuff.

This is where the LFS will shine above all!

Talking-to people who live, breathe, and sleep aquarium-keeping will help. Vendors online- same thing applies.  Hobby forums have a responsibility for perpetuating a responsible, educational culture. Too much is at stake. When PIJAC stats show that the average person is in the hobby for only 18 months before throwing his/her arms up in frustration, something is wrong.

Especially when we are selling millions of dollars of expensive equipment and livestock to the very people who are bailing out in droves. This isn’t just a fight to create more understanding and awareness..It’s literally a fight for survival of the hobby and art of aquarium keeping. Yup.

This is a “cultural shift”

Pure and simple…In a world where people are supposedly not able to retain more than 280 characters of information, and where there is a apparently an “algorithm” for pretty much everything, some prognosticators will assert that we simply have lost the ability to absorb information on things that are not considered “relevant” to our immediate goal.

If the immediate goal is to have a great looking tank, apparently we don’t want to take the time to learn the groundwork that it takes to get there and to sustain a system on a long-term basis. It’s far more interesting- and apparently, immediately gratifying- to learn about what gear or products can get us where we want, and what fishes, corals, and plants are available.

I don't buy any of this, but the problem is, we as a hobby tend to function as if this is, indeed, the way things are.

We perpetuate this by well- dumbing everything down. We feature the superficial aspects of the hobby- how cool the tanks look, etc., while failing to get people to grasp the basics. You even see this in many of the “build threads” I alluded to previously.

This is a huge thing in the "Reef" side of the hobby. In many of these threads, you’ll see a detailed run down of the equipment, shots of the assembly, the “solutions” to the problems encountered along the way (usually even more expensive equipment purchases). You’ll see pics of the finished tanks and healthy fishes and corals…

All very interesting and even helpful, but the “weirdness” starts when, in the middle of the threads, you’ll see the “builder” asking about why he’s experiencing a massive algae outbreak, or why all of the coral frags he just added are dying in this brand new, state-of-the-art tank. Often, they'll blame a "bad batch of salt" or a pump that doesn't quite work as advertised. Yet, the continued questions and ensuing discussions make you wonder why this ill-informed, yet apparently financially comfortable individual went off on a 5-figure “joyride”, building a dream tank with an apparent complete ignorance of many of the hobby fundamentals.

I’m often dumbfounded at the incredible lack of hobby basics many of these people show. Just because you’re a great DIY guy, or have disposable income to buy everything you see advertised online for your 400-gallon reef tank, it doesn’t make you a knowledgeable or experienced hobbyist. It just doesn’t.

 Algae, the nitrogen cycle, fish diseases- none give a shit about that!

Okay, I’m sounding very cynical. And perhaps I am. But the evidence is out there in abundance…and it’s kind of discouraging at times.

It doesn't HAVE to be that way, either.

Look, I’m not trying to be the self-appointed "guardian of the aquarium hobby." I’m not  simply "calling us out." I'm not lamenting progress in our civilization...I’m asking for us to look at this stuff realistically, however. To sort of hold ourselves accountable. Yes, no one has a right to tell anyone that what they are doing is not the right way, but we do have to instill upon the newbie the importance of understanding the basics.

Like many other vendors, I offer  products to people and don’t educate them on every single aspect of aquatic husbandry. It’s hard to do that. I do write lots of blogs and articles, and lecture all over the world, so I know I’m doing something to reach some people…but likely not enough. I think that I need to do better. I will continue to write more about basic sort of stuff and how it impacts our speciality than I do about whatever the heck is on my mind? 

Does this help? I Don't know.

I do know that we all need to tell hobbyists stuff like it is, without sugar-coating everything. . There are dozens of posts and “build threads” on forums and Facebook groups that DO provide great information to hobbyists, along with plenty of articles by experienced aquarists discussing any number of arcane and fascinating aquarium-related topics. Great YouTube channels, like that of our good friend, Rachel O'Leary, which provides amazing information that will flat-out make you a better hobbyist.

Yet, for all of this, we still see what appears to be a very "superficial"understanding of the hobby by so many hobbyists. I feel sorry for these people, as well as the animals that are exposed to potentially fatal situations out of pure ignorance.

These hobbyists also miss the joy that comes with understanding and applying something that they have learned.

We need to stress this more.

Look, we all make mistakes. Part of the hobby and the learning curve. No one seems to want to talk about that. No one wants to present the "dark side" of the hobby now and then. We need to talk about this stuff. Sure, it's more fun to just show the kick-ass finished aquarium and it's award-winning aquascape.

Yet, when I see so many indications that hobbyists are just not grasping the basic information that they need to be successful, I feel a sense of disappointment. I feel like we- all of us who are experienced in this great hobby and industry- are possibly  letting down a whole generation of hobbyists. Yikes, I’m giving us a bit of an ass-kicking. Yeah. I think we need to sit down with prospective hobbyists and show them that learning about the basics is actually FUN. It’s actually really cool stuff that will make their hobby experience way more fulfilling and interesting.

How does this get solved?

Well, it starts with mentoring. It not only starts with getting people excited not only at the end result- owning a “slice of the bottom”- it also starts with getting people excited about the journey to get there, and learning about how we can make the animals under our care thrive. It’s not just about the latest gadgets- it’s about the latest information on fundamental care of animals. We should share more information and pictures about the amazing wild habitats from which our fishes come, and discuss how these same processes apply in our aquariums- and how we can replicate many aspects of Nature in our own homes.

It starts by us once and for all embracing the local fish store and the people who work there. Sure, there are the stories of ignorant personnel and such- but these are truly the exceptions rather than the rule- yet they have somehow seeped into our collective consciousness and contaminated forever our view of the local fish store- compelling many hobbyists to seek out the answers they want-or worse- the answers they want to hear- from unvetted sources online.

The reality is, most fish stores and hobby vendors do give invaluable, free hands-on advice. Most attempt to instill a passion that goes beyond just shilling products, an accusation that is often unfairly leveled upon them. Enough is enough. Just like acknowledging that not all online coral vendors are Photoshop-abusing, money-grabbing deceptive-business-practicing sharks, or every E-Bay aquarium advertiser is not a no-service, deceptive sleazebag working out of the back of his car...we cannot keep pinpointing the LFS as the primary cause of hobby dissatisfaction and misinformation.

The local store, as I’ve written about previously- is the first link to the wonders of the hobby, a cornerstone of hobby “culture”, and the owners and employees deserve our unwavering support. Like all of us- they deserve the occasional kick in the rear when they screw up. But that’s about it. 

Making positive hobby changes also starts by continuing to emphasize basic care...Example: How many hobbyists do you know who really embrace a quarantine protocol for any fish added to their tanks? How many hobbyists do you know that would bend over backwards to buy a product that promises the benefits of quarantine without actually doing it? A lot, I'll bet...I mean, we'd all be tempted...but how many would really just jump on that because of the seemingly easier course?

Human nature? I guess.

As aquarists, we need to support new hobbyists with not just the generosity that we’re famous for, but the incredible passion that we curate. We need to give them the good and the bad information. We need to impress upon them that running without learning how to walk first is a painful way to learn. Fishes, plants and corals are not just “merchandise”, and the learning curve should not include exposing them to potentially fatal situations that could have been avoided had the neophyte hobbyist been properly instructed about their requirements from the get go.

We need to let beginners know that part of the joy of the hobby is learning about this stuff first hand..by doing it.

In an era of "instant gratification", it just seems that the aquarium hobby is a polar opposite. The vast majority of us get it, but there is a discouragingly large portion of the aquarium keeping hobby that hasn't seemed to have grasped the concept just yet. 

Let's do our best to help change that.  

We have it easily in our power to "fix" this...It starts with really easy stuff:

Support your LFS. Support your fave online vendor. Support your fellow hobbyists. Actively recruit members for your local aquarium club. Remember, there are no real "hacks"- no shortcuts- in this game. Yet, there are always processes. Learn about them. Teach them. Enjoy the journey.

Stay inspired. Stay excited. Stay motivated. Stay inquisitive. Stay helpful. Stay generous. 

And always Stay Wet.

Scott Fellman

Tannin Aquatics

January 13, 2020


Brackish water aquariums- from the bottom up!

Want to know a little secret?

Tannin Aquatics almost didn't happen! I came very close to doing something quite different! (I know at least a few "competitors" and people who've tried to copy/rip-off our company recently that would have LOVED that, lol)


There was this other lifelong obsession of mine, which seemed to my friends to be a more logical transition for a geeky aquatics entrepreneur...


Yeah, brackish. As in, brackish water aquariums; mangrove estuaries, intertidal habitats...

I was familiar with these habitats, both as an aquarist and as a traveler, having spent many happy hours in stinky, mosquito-filled tropical backwaters, often knee-deep in mucky soil, poking around the mangroves with the delight that only a fish geek can take!

I had kept brackish tanks for years...a natural compliment to reef tanks; and, at the time, it seemed a good way to transition from the coral world, at least!  I figured that the "Tannin thing" would come later, a natural "digression" from salt-sequentially, if you will. Brackish made sense for someone who had his head firmly in the saltwater world for decades, both as a hobbyist and later, as a business person.

I mean, it wasn't going "all the way" fresh, so it wouldn't have to "wean myself" with as much effort. I developed a brand, product ideas, and all the trappings you'd expect from someone who is totally into something. The aquarium world's first completely dedicated brackish-water vendor. Talk about "niche!"

Yeah, it was pretty serious!

Then I stopped it. Cold.

As you probably have guessed, this "sub-obsession" ultimately morphed into "Estuary", our brackish-water line of natural materials here under the larger Tannin Aquatics "umbrella."

And that's played out pretty well, I think. We've done quite a bit of work with our version of the formerly moribund brackish-water aquarium. One that is dynamic, unique, and altogether different that what has been proferred in years past.

And the whole thing centers largely around Mangroves...

Mangroves are woody plants which grow at the interface between land and water in tropical and sub-tropical regions. Mangroves are what botanists call "halophytes"- plants that thrive under salty conditions. And they do very well in higher-nutrient substrates!

And, like with our freshwater botanical-style aquarium obsession, we'd do well to study these habitats for replication in our aquariums...

In many brackish-water estuaries in the tropics, rivers deposit silt and mud, which generates nutrients, algae, and fosters the development of other small organisms that form the base of the food chain.

This "food chain" is very similar to what we've been talking about in our botanical-style blackwater aquariums. We've spent a lot of time trying to recreate various aspects of food chains in our botanical-style aquariums, and this is a perfect extension of that practice.

The nutrients the mangroves seek lie near the surface of the mud, deposited by the tides. Since there is essentially no oxygen available in the mud, there is no point in the mangroves sending down really deep roots. Instead, they send out what are called "aerial roots" (that's what gives them their cool appearance, BTW), sort of "hanging on" in the mud, which also gives the mangroves the appearance of "walking on water."

And of course, you know that we have a more than "casual" interest in substrates, right? The composition of the substrates where mangroves reside is very interesting, and as aquarists, we'd do well to refer to some studies of these habitats.

Mangrove soils are an interesting, nutrient-rich mix of marine alluvium, transported as sediment and deposited by rivers and the ocean tides. Soils are made up of sand, silt and clay in various combinations. Mangrove soils are typically saline, anoxic, often acidic and frequently waterlogged.

A real "cocktail" of variables, right?

You often hear the substrate in these habitats referred to as "mud." In this context, of course, "mud" actually refers to mixture of silt and clay, both of which are rich in organic matter. The "topsoil" is a combination of sand or clay. Now, interestingly, the lighter-colored topsoils, consisting largely of sand, are pretty well aerated. The clay-like topsoils are far less aerated.

In a recent study of these habitats which I stumbled on, the researchers concluded that the composition in typical mangrove habits was as follows: "Overall sediment proportion of main fractions is 59% for silt, 21% for sand and 20% for clay."

Of course, this has some implications for those of us who are trying to recreate this type of habitat in our aquariums, doesn't it?

Mangrove habitats are usually enclosed and protected environments, with low-energy waters, which is conducive to sedimentation of clay particles. Now, confusing the matter further is that various studies of tropical mangrove forests worldwide have revealed that mangrove soils may be either acidic or alkaline, depending upon the materials deposited within them. 

In mangrove soils, nitrogen is considered the primary nutrient that affects species composition and mangrove population density. Further analysis found that nitrogen and phosphate influence structure and composition in approximately equal proportions. Potassium is beneficial for mangrove growth, yet vitally important in higher salty environments, as it impacts the osmotic regulation that occurs within the mangroves themselves. So, if you're keeping mangroves in very salty conditions, dosing a fertilizer containing potassium might be quite beneficial!

Now, we talk in general terms about mangrove soils being "nutrient rich"- and they are, for the most part. However, there are significant variabilities because of the dynamics of the mangrove habitat. Although some mangrove soils have extremely low nutrient availability, this factor varies greatly between mangroves- and also within a mangrove stand! In other words, the mangroves themselves actually influence these factors! 

In general, it's understood by ecologists that nutrient-rich silty sediments produced faster growth of mangrove seedlings- vital in this important ecosystem- and of extreme interest to those of us who wish to sprout and grow mangrove propagules in the aquarium!

And of course, the leaves which mangroves regularly drop form not only an interesting aesthetic and "structural" component of the habitat (and therefore, the aquarium!)- they contribute to the overall biological diversity and "richness" of the habitat. 

Fungi and bacteria in brackish and saltwater mangrove ecosystems help facilitate the decomposition of mangrove material, just like in their pure freshwater counterparts.

Interestingly, in scientific surveys, it's been determined that bacterial counts are generally higher on attached mangrove leaves than they are on freshly-fallen leaf litter, and this is kind of interesting, because ecologists feel that attached, undamaged mangroves leaves don't release much tannin, which, as we know might have some anti-bacterial properties. However, it's also been found that materials like humic acid, which are abundant in the mangrove habits, stimulate phytoplankton growth there. 

Interesting, right?

Yeah, leaf drop is a big deal in mangrove habitats! And this phenomenon is something we can- and should- replicate in our aquariums!

The high level of carbon "allocation" to roots of mangroves, in conjunction with mangrove litter fall, and the rather low rates of decomposition which occur in anoxic soils, results in mangrove ecosystems being quite rich in organic matter. And despite these lower rates of decomposition, the mangrove leaf litter is a major source of nutrients in the mangrove ecosystem!

Yeah, leaves again!

The leaves of mangroves, as they break down, become subject to both leaching of the compounds in their tissues, as well as microbial breakdown. Compounds like potassium and carbohydrates are commonly leached quickly, followed by tannins. Fungi are the "first responders" to leaf drop in mangrove communities, followed by bacteria, which serve to break don't the leaves further.

And of course, higher organisms like shrimp, crabs and mullosks are the dominant organisms in these ecosystems, performing an important role in "processing" leaves and other organic materials which accumulate in them.

Organisms found in mangrove habitats are referred to as either "epifauna" or "infauna", and they perform different roles within the ecosystem. "Epifauna" refers to those invertebrates that live on various substrates such as lower tree trunks and the sediment surface, but which do not burrow into it. Gastropods, crabs, and bivalve species are typical representatives of the epifauna in mangrove ecosystems. "Infauna" refers to burrowing invertebrates, which live within the sediment, and includes crabs, shrimps, polychaete and sipunculid worms.

And then, there are the fishes, of course.

So yeah, we love the idea of creating your brackish water ecosystem around leaves and mangroves (either alive, or just utilizing the roots/branches to simulate the appearance of the mangrove root system). The possibilities are endless for creating fascinating aquariums and unlocking some cool secrets!

Those of you who have experience with both aquatic plants and botanical-style aquariums will really enjoy our interpretation of the brackish water habitat. And, if you're also a marine aquarist, that "skill set" can only help, too! 

Yeah...there is so much going on in this area...so much for us to play with as hobbyists, In fact, part of me is actually a bit guilty for unleashing the "Estuary" idea so early on (2.5 years) in Tannin's existence, as we were just starting to venture out and unlock some secrets in the blackwater/botanical game...But I think that the two can continue to develop together and spur on new hobby advances.

In fact, I think that they already have...

So, if you were contemplating playing around with this whole brackish water/botanical-style aquarium game, it's a really good time to experiment! We're looking forward to seeing more an more of your experiments and ideas coming to light...in this tinted, slightly salty world!

Stay curious. Stay resourceful. Stay bold. Stay excited. Stay adventurous. Stay creative. Stay enthusiastic...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


January 12, 2020


The opportunities of microhabitats...

There is a "big picture" in Nature- vast habitats, filled with life; encompassing a myriad of intricate locales and ecological relationships.

And then, there is the 'small picture"- the very niches which form the vast aquatic habitats of the world. They're fascinating.

We talk a lot here about "microhabitats" in Nature; little areas of tropical habitats where unique physical, environmental and biological characteristics converge based on a set of factors found in the locale.

The mind-blowing diversity of Nature is comprised of millions of these little "scenes", all of which are the result of various factors coming together.

As aquarists, observing, studying, and understanding the specifics of microhabitats is a fascinating and compelling part of the hobby, because it can give us inspiration to replicate the form and function of them in our tanks!

We spend a lot of time discussing and considering the various components and interactions of water and terrestrial habitats, such as the igarape and the surrounding igapo and varzea flooded forests, and the Pantanal- those amazing inundated meadows found in Brazil.

These environments are fascinating, because they are examples of what happens when temporary situations (ie; floods) affect the  "topography" of terrestrial habitats. Our pages and posts feature amazing pics by David Sobry, Mike Tuccinardi, and Tai Strietman- all who observe Nature with a hobbyist's eye!

Ecologically, the productivity and diversity of these habitats make them perfect subjects for replication in our aquariums. Not only do they offer unique aesthetics- they offer really cool opportunities to see how they can function in a closed system like an aquarium!

When fishes are kept in a representation of a habitat which mimics its form and function, enormous potential for discoveries and success present themselves! Behaviors are different. Feeding patterns are different.

The whole "vibe" is different.

Look at the way rocks, soil and branches come together in flooded forests, meadows, and rivulets to form interesting physical spaces that fishes utilize for protection, foraging, and reproduction. 

By replicating the complex look and physical attributes of these features, including rich substrate, roots of various thickness, and leaves, we offer our fishes all sorts of potential microhabitats. In the aquarium, we tend to focus on the "macro" level- creating a nice wood stack, perhaps incorporating some rock- but we seldom see the whole picture allowed to come together in a more natural way. 

This was what inspired me in a recent iteration of one of my office "igapo-inspired" blackwater aquarium. The interaction between the terrestrial elements and the aquatic ones. Allowing terrestrial leaves to accumulate naturally among the "dormant terrestrial plant and  root structure" we created fostered this more natural looking, more natural-functioning environment.

As these leaves began to soften and ultimately break down, they encouraged microbial growth, biofilms, and fungal growths- all of which provided food for the resident fishes. No supplemental feeding was provided, and the fishes thrived.

..Just like what happens in Nature when these elements combine. There is something alluring to interpreting this in the aquarium.

Facilitating these processes- allowing the materials to accumulate naturally and break down "in situ" is a key component of replicating and supporting these microhabitats in our aquariums. It's a leap of faith- a bit of a stretch- sort of counter-intuitive over most of what we do in the hobby.

The typical aquarium hardscape- artistic and beautiful as it might be, generally replicates the most superficial aesthetic aspects of such habitats, and tends to overlook their function- and the reasons why such habitats form. In some cases, it's almost "sterile"- and I suppose there is a certain beauty to that, too.

Yet I urge you to go further in the other direction now and again.

When I see such beautiful aquascapes, I'm almost always thinking to myself, "Damn, they're sooo close to being gable to create something really natural here!"

If I had one of these tanks now, it would literally take every bit of resistance I can offer to avoid tossing in some leaves and botanicals into the nooks and crannies that are formed where substrate, stones, dormant terrestrial plants, and roots meet. Purely aesthetic 'scapes to me are like "missed opportunities" to learn more about these fascinating microhabitats!

So my plea to you- my fellow natural-style aquarium lovers- is to consider the function of microhabitats; what they formed, how fishes can live in them, derive protection, food, and utilize them as spawning locations from them.

Sure, you may not like to pile on the leaves and botanicals into your woodwork. You might not want to see all of that sediment, biofilms, and stuff breaking down in the nooks and crannies...

I get it.

However, don't automatically dismiss the idea out of hand, either ...

You can always remove these materials if they offend your aesthetic sensibilities. I only ask that you give the idea a try...a good, serious look at the elegance and function of these amazing ecological niches...

The "microhabitats" where substrate, leaves, and roots meet create amazing opportunities to create unique, functionally aesthetic aquariums.

Think about it.

Stay thoughtful. creative. Stay studious. Stay observant. Stay creative. Stay diligent...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


January 10, 2020


Freezing time? Or embracing the process?

There's nothing quite like a brand new aquarium; one filled with promise and potential. In the botanical-style aquarium, the aquarium looks quite a bit different than it will ultimately appear- the botanicals are clean and untouched by biofilms, the leaves appear crisp and largely intact, and the wood and substrate are typically sharp and free of that "patina" of growth that occurs over time.

Crisp. "Fresh." Clean-looking.

And that's nice, I suppose. I mean, it IS.

It meets the hobby's broadest "expectations" of just how an aquarium should look. At least, from a "neatness" standpoint, right? Many hobbyists- and I"m convinced, many more- would embrace the botanical-style aquarium more wholeheartedly if they could keep their systems sort of "frozen" in time at that point.

Yet, to many of us, the real "allure" of the botanical-style aquarium is what takes place after those first glistening weeks- the time period when the aquarium starts to evolve, take on an even more natural look, and becomes more of an ecosystem, as opposed to a primarily aesthetic display.

Of course, there are lots of ways to manage the establishment, "evolution" and long-term function of the botanical-style aquarium. You could regularly clean, remove, and replace all of your botanicals and leaves as they start to acquire that patina of biofilm, soften, and decompose. You could brush off all the biofilms, stir up and siphon the substrate, and literally "freeze" the aquarium in that "fresh-from-the-showroom" phase!

There is a sort of happy medium, of course.

You can retain much of the "baseline" look by leaving the bulk of the botanicals in place, perhaps removing/replacing a few selected pieces from time to time. This gives you a sort of "established" look, and doesn't remove all of the "function", offering you a manageable option to keeping your aquarium more-or-less "fresh.

Or, you can simply allow much of the material to remain in play, and add new pieces as you see fit. A sort of actively-managed "evolutionary" process. One that not only mimics Nature in many respects (I mean, leaves and seed pods and stuff are constantly falling into, or being swept by currents into, aquatic habitats, right?), it will keep the microorganism/fungal/microcrustacean population aquarium biologically "fueled up", with a continuous supply of new food sources...just like in Nature!

The continuous replacement and supplementation of leaves and botanicals as they start to break down is a sort of process- okay, maybe even a habit- which many of us who play with botanical-style aquariums. This not only creates a continuously evolving aesthetic, it helps maintain the biological diversity and environmental parameters are held in the cherished "tight range".

Variation on a theme: I know a few "tinters" who make significant replacements of leaf and botanical items, taking out a lot of the older materials, while  replace them with fresh materials simultaneously, and this is conducted on a regular, although infrequent basis. This is similar to the Japanese aquascaping practice of "sozo haishoku" espoused by Takashi Amano, which is the processs of removing of as much old substrate material as possible along with the plants it contains in an aquarium, and replacing them with new materials.

It preserves the overall "composition" of the layout, but the "softscape" (the botanicals and leaves, in our case) could change dramatically over time. 

This process is very interesting to us as botanical-style aquarium fans, because, as we talked about many times before, it does sort of mimic what happens in many streams and rivers on a seasonal basis: Older materials are swept downstream as the watercourses swell, and are replaced by new ones that arrive to replace them.

And of course, in the aquarium, performing a "sozo haishoku"-type replacement of materials can significantly change the aesthetic of the aquascape because the botanicals are replaced with different ones after the previous ones are removed. It essentially means that your aquarium will significantly change over extended periods of time, likely bringing a very different look to the tank at different points in its operating "life cycle."

On the "downside" (there's always one, right?), it can also create significantly different environmental parameters when we do big "change-ups" of materials in a short span of time; the impacts on our fishes may be positive or negative, depending upon the conditions which existed prior to the move. 

Now, personally- I'm a fan of less "radical" moves, and in the interest of a good "offense", I favor regular, more measured additions to the botanical "set" in my aquariums. I tend not to remove any decomposing botanical material, unless it becomes an aesthetic detraction because it's blowing all over the place or something like that.

I while back, I did a slight "makeover" to my brackish water mangrove tank in my home office, which has accumulated a significant amount of decomposing mangrove leaf litter over the year it has been in operation. I wanted to add a lighter-colored, fine sandy substrate to be more consistent with some of the brackish-water Mangrove habitats I've studied. So what did I do? Well, I literally placed the sand on top of the accumulated leaf litter detritus...

A pretty radical move for me!

And really, what happens is that, through the power of the current and the activities of my fishes, some of it rises up to the surface once again! And the water parameters have been unaffected by this move. With the understanding that we are attempting to foster multiple "levels" of life forms in our tanks, NOT removing all of the decomposing materials is a good move, IMHO. 

That was my "closest approach" to the process of "sozo haishoku", I think!

Think about food chains, microbial growth, and environmental stability in our aquariums. Fostering these requires us to embrace, rather than fear- some of these processes as they happen in our tanks. 

And of course, Nature provides examples of similar processes.

Of course, I have no illusions that open, natural aquatic systems operate differently from our aquariums, but the "concept" is essentially the same... Study this pic by our friend, Tai Strietman taken in the Amazon...Leaves being covered by sand...interesting! Nature provides a "prototype" for everything, huh?

Having studied many images of Amazonian igarapes, it is very obvious that, although some materials are swept away by currents, etc., many do remain in place until they fully decompose, adding to the richness and complexity of the habitat, and that we can mimic this process in our aquariums to some advantage.

And, when coupled with good husbandry technique (ie; water exchanges, population management, feeding, and use/replacement of chemical filtration media) an eye for aesthetics, patience, and a focus on creating as complete-functioning a microcosm as possible in our tanks, long-term success is virtually a given in botanical-style aquariums.

Okay, emphasis on "virtually." Nothing is a complete "given" in this hobby!

Now, far be it from me to say that one of these systems won't test your patience, diligence, and perseverance- but to those who do endure and hold steady, the rewards are there. Facing, accepting, and dealing with some of the early "aesthetic challenges" in botanical-style aquariums, like the appearance and proliferation of biofilms, fungal growth, and the breakdown of botanicals is a fundamental step in building our "skill set" in this speciality.

A mental shift.

And of course, you can take radically different starting approaches, as I've done recently- creating aquariums which "look" established right from the start, because you're immediately utilizing materials which foster rapid growth of biofilms, decompose quickly, and develop fungal/microbial populations more rapidly.

I have found this process, utilizing different combinations of soils and sediments, mixes of highly ephemeral and durable botanical materials, and a variety of wood and roots, to create some fascinating microcosms which mimic the wild aquatic habitats we love in a surprisingly realistic and highly functional manner.

As every botanical-style aquarist knows, it's simply a fact that terrestrial materials, which exposed to water, will decompose, recruit fungal and biofilm growths, and substantially impact the aquatic environment and the physical appearance of our tanks.

Exactly like in Nature!

There is tremendous beauty in the ephemeral nature of aquatic habitats. At every phase of their existence, they are productive, beneficial, and appropriate for the various life forms which inhabit them.

It's no different in the aquarium. Stuff get's covered in biofilms. It begins to break down. Its appearance changes, and the aquarium habitat evolves.  We need to embrace this process, understand it...Hell, we need to celebrate it! We don't always have to continuously "edit" the process. And how we manage this stuff, both mentally and practically, will impact the state of the art of truly "natural" aquariums for years to come.

There is more to these types of aquariums than just aesthetics.

There is the function. The evolution. The processes.

For decades, the hobby focus has been all about removing pretty much everything from aquairums as soon as it breaks down. I beg us to reconsider this long-held belief, and to think about the potential benefits of leaving materials in the tank to break down in situ.

The benefits, as we've talked about many times, are numerous- ranging from environmental consistency to continuous production of supplemental food sources for our fishes. An un-interrupted chain of life fostered in the botanical-style aquarium can yield amazing results. 

We just have to give it the chance to "find its way..."

So, if you're tempted to remove all of the decomposing leaves or broken-down botanicals to preserve some aesthetic you have in your head...think twice, okay?

Preserve some of the old materials. Mix in some new ones. Re-distribute existing materials.

Or not.

Think about the long-term impacts of such short term moves. Do think about the ability of the life-forms in our tank to process and utilize these materials if left undisturbed. Yes, consider the concept of "Sozo Haishoku", the transient nature of botanicals, and the evolution of your aquarium over time.

You might change the entire course of your aquarium- and you will almost certainly change the entire course of the hobby as a whole.

Stay observant. Stay curious. Stay diligent. Stay consistent. Stay thoughtful. Stay engaged...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



January 09, 2020


Falling Trees. Rising Ecosystems. New Approaches...

Virtually every time we plan an aquascape, it seems like one of the most major components of the composition is wood. It's been that way in the hobby for years. Sure, you see some rock-based scapes (like "iwagumi"-themes), but if you ask most aquarists, they'll tell you that the basis for almost any aquascape has to be wood of some sort. And it makes sense. Wood adds a sense of color, texture, and depth to any aquascape.

It makes or breaks it, in many cases, right?

A good part of the aquarium "practice" is the use of various types of wood. Hobbyists have actively sought out and used all sorts of wood for use in aquascaping pretty much as long as the hobby has been around! 

And why not? Using wood in our aquascaping creates beautiful, useful 'scapes that provide a great home for our fishes, and delight our aesthetic sensibilities.

And of course, branches and twigs and other tree parts are ubiquitous in the wild aquatic environments of the world.  And many of you are absolutely incredible at 'scaping with wood! Collectively, we've developed extreme talent for creating fantastic designs with all sorts of wood.

However, there is more to this stuff than just the good looks, right?

Of course! There is a functional benefit that is as beautiful- if not more so- than the aesthetics themselves. 

Let's focus for a bit on the ecological "role" that tree branches, trunks, and other wood play in the wild aquatic ecosystems of the world. Doing this helps give us not only "context" as to how they function, but what impact they have on the overall aquatic habitat. This is an extremely helpful context when we decide to play with wood in our aquariums!

One observation I've made over the years is that most of the wood we use seems to be more of the "branchy" type, as opposed to  pieces reminiscent of say, a tree trunk or very large branch, as you might often find in Nature?

More on that in a bit.

In Nature, it is not uncommon at all for small (and large) trees to fall in the rain forest, with punishing rain and saturated ground conspiring to easily knock over anything that's not firmly rooted!

When these trees fall over, they often fall into small streams, or in the case of the varzea or igapo environments in The Amazon ( the ones that I'm totally obsessed with), they fall and are ultimately submerged in the inundated forest floor when the waters return.

And of course, they immediately impact their (now) aquatic environment, fulfilling several functions.

Fallen trees provide a physical barrier or separation from currents, accumulating leaves, sediments, and detritus- all important as food sources to a huge number of aquatic organisms. They also provide a "substrate" for algae and biofilms to multiply on, and providing places for fishes forage among, and hide in. Many fishes, like small cichlids, will reproduce and raise their fry among these fallen tree trunks.

An entire community of aquatic life forms uses the fallen tree for many purposes. And the tree trunks, branches, and other parts of the tree will last for many years, fulfilling this important role in the aquatic ecosystems they now reside in each time the waters return.

Let's focus on this "ecological component" for just a bit.

Shortly after falling into the water, fungi and other microorganisms act to colonize the surfaces, and biofilms populate the bark and exposed surfaces of the tree.  Over time, the tree will impart many chemical substances, (humic acids, tannins, sugars, etc.) into the water.

The fallen tree literally brings new life to the waters.

I can't stress enough how interesting and important this transformation of the terrestrial environment to the aquatic one is. It helps explain so much of why the aquatic habitats look and function the way they do, and how they impact the life forms which make use of them.

The materials that comprise the tree are known in ecology as "allochthonous material"-  something imported into an ecosystem from outside of it.  (extra points if you can pronounce the word on the first try!)  We've talked about that stuff for a while now, right?


And of course, in the case of fallen trees, this includes includes leaves, fruits and seed pods that fall, or are washed into the water along with the branches and trunks that topple into the stream.  

These materials are known to ecologists as “coarse particulate organic matter” (CPOM), and in the waters of these inundated forest floors there is a lot of CPOM, and the community of aquatic organisms (typically the aforementioned aquatic insects and crustaceans) has a high proportion of “shredders”, which feed on the CPOM and break it up into tinier bits called (wait for it...) "fine particulate organic matter" (FPOM).

And of course, some fishes, like larger characins, catfishes, etc., consume fallen fruits and seeds as part of their diet as well, aiding in the "refinement" of the CPOM, as well as helping spread the undigested seeds throughout the forest floor, ready to sprout when the waters recede.

Other organisms make use of the fine particulate matter by filtering it from the water or accessing it in the sediments that result. These allochthonous materials support a diverse food chain that's almost entirely based on our old friend, detritus!

Yeah, that detritus.

The stuff of nightmares for many dyed-in-the-wool hobbyists...The stuff of dreams for many hungry fishes who consume it and the associated fauna within it! It's so incredibly important to aquatic organisms that I can't even begin to stress it enough!

And, although the forest floor receives substantially less sunlight than open rivers, the nutrients and available light are utilized by algae, which may colonize the surfaces facing up into the sun. And of course, many fishes make use of these algal films as a food source...Sensing a theme here?


Fallen, submerged trees are of enormous importance as a provider, facilitator, and accumulator of food for aquatic organisms.

We see similar results in our aquariums, right? "Undefended" surfaces are colonized by algal "patinas" and biofilm growths. These growths may look a bit "unconventional" to many hobbyists, but their appearance belies their elegance and beauty as indispensable components of a complex aquatic ecosystem.

And of course, the tree, like almost anything that is submerged, will gradually decompose over long periods of time. This process is actively exploited by aquatic life forms at all levels. Hollowed-out sections will be inhabited by fishes and exploited for the shelter they offer, and of course, the aforementioned crustaceans and insects will utilize the tree and its constituent materials in various ways.

And, as for the fish population, it's long been known by ecologists that fish movement, species richness, diversity, and population density are directly affected by the physical and biological influences of... fallen trees!

And the deep beds of leaves that may be "corralled" by the fallen trees- a sort of natural "dam"- play an important tole in determining what fishes live in these "microhabitats." Deep accumulations of leaves, as we've discussed before, will definitely limit some fish species, which cannot tolerate the lower oxygen concentrations found in these areas, yet attract others which make use of the life forms living on the surface layers of the leaves.

Other fishes take advantage of the "physical barrier" that a fallen tree presents to shelter from predatory species. Many adaptations have taken place over eons to allow fishes to exploit these changes to their environment caused by fallen trees!

It's pretty fascinating stuff, all of which has implications for us as aquarists who want to replicate natural habitats to the most realistic degree possible. As aquarium hobbyists, what does this all mean to us? How can we employ the lessons learned from fallen trees in Nature? What can we do to mimic this?

Well, for one thing, I think it's a call for us to consider employing some bigger, thicker pieces of wood in our tanks!

Now, sure, I can hear some groans.

I mean, big, heavy wood has some disadvantages in an aquarium. First, the damn things are...well- BIG- taking up a lot of physical space, and in our case, precious water volume.  And they're likely not as sexy as those awful "bonsai trees" that are (regrettably) becoming popular again...

And, of course, a big, heavy piece of wood is kind of...pricy.

And physically cumbersome for some. Although wild habitats are filled with big old tree trunks, stumps, and branches, scenes just begging to be recreated in aquariums, we tend to hesitate...

There are many 'scapers who would make the case that you can't make big, gnarly pieces of wood "work" in an aquarium because of their impact on "ratio" and "proportion", etc... You know, the "artistic" part.

And to these types, I gently admonish you to check out the works of some talented 'scapers, like our friend, Mitch Mazur, who have made that now-famous "mental shift" to work with Nature in an artistic interpretation...

These pleas and "look what HE did!" sort of arguments are almost a "prerequisite" of late when I talk about any idea that has an aesthetic component to it, because the self-appointed "guardians of aquascaping style" seem to come out of the woodwork (lol) after these discussions, reciting dozens of well-rehearsed reasons why the concept won't work, rather than even trying to do something similar. 

It's weird. 

To that, of course, I call, "Bullshit!"


Yeah, a big piece of wood or dense aggregation of smaller pieces in an aquarium does create some challenges, but most of them are in our head. Hell, Takashi Amano himself did a few amazing tanks with huge pieces of wood years ago. Remember?

And of course, when we utilize a large piece of wood (relative to the aquarium's water volume), it has a chemical and physical impact on the aquatic environment that is...hey- sort of similar to that which occurs in Nature, right?


Now, on a purely practical level, let's think about the very practices we employ when utilizing wood in our aquariums. It starts with the preparation process...

When you first submerge wood, a lot of the dirt from the atmosphere and surrounding environment comes off, along with tannins, lignin, and all sorts of other "stuff" from the exterior surfaces and all of those nooks and crannies that we love so much.

And of course, there are the tannins. Now, I don't know about you, but I'm always sadistically amused by the frantic posts on aquascaping forums from hobbyists that their water is turning brown after adding a piece of driftwood. I mean- what's the big deal?

Oh, yeah, not everyone likes it...I forgot.

The reality, as you probably have surmised, is that driftwood will continue to leach tannins pretty much for as long as it's submerged. As a "tinter", I see this as a great advantage in helping establish and maintain the blackwater look, and to impart the humic substances that have been proven to be very beneficial to the health of almost all freshwater fishes.

It's a unique aesthetic, too, of course!

When it comes to preparation, I'm more concerned with those impurities- the trapped dirt and such contained within the wood.

As you probably know, that's also why I've been a staunch advocate of the overly conservative "boil and soak" approach to the preparation of botanicals, too. A lot of material gets bound up in the dermal layer of the tree where the wood comes from. The bulk of the dry mass of the xylem (the "network" within the tree which transports water and soluble mineral nutrients from the roots throughout the plant, and comprises what we know as "wood.") is cellulose, a polysaccharide, and most of the remainder is lignin, which is a sort of complex polymer. 

Why the mini botany lesson?

Well, because when you have some idea of what you're putting into your tank, you'll better understand why it behaves the way it does when submerged! In a given piece of driftwood, there is going to be some material bound up in these structures, and it will be released (gradually or otherwise) into the water that surrounds it, with a big "burst" happening on initial submersion. 

This is why, during the first couple of weeks after you submerge wood, that the water often becomes dark and even cloudy. There is a lot of "stuff" in there!

It's far better, in my opinion, to take the time to start the "curing" process in a separate container apart from the display aquarium. This is not rocket science, nor some wisdom only the enlightened aquarists attain. It's common sense, and a practice we all need to simply view as necessary with terrestrial materials like wood and botanicals. You may love the tannins as much as I do, but trust me, your tank could do without the polyscaccharides and other impurities from the outer layers of the wood.

The potential affects on water quality are significant!

Here is a natural corollary: It's pretty plain to see that at least part of the reason we see a burst of new algae growth and biofilm in wood recently added to an aquarium is that there is so much stuff bound up in it. Algal and fungal sports can literally "bloom" during the initial period after submersion. It's exactly what happens in the wild aquatic habitats of the world when tree trunks and branches are covered by water.

On the other hand, the adventurous aquarist in me can't help but wonder if we should just give the wood a thorough washing, and let this whole process play out in the aquarium, to foster this amazing biodiversity within the aquarium itself. Again, this is an example of setting up an aquarium from the start to replicate both the form and function of Nature.

Yes, it will look different. Yeah, you'll see a lot more biofilm, fungal growth, detritus, and perhaps even slightly hazy water. You'll have to carefully monitor the nitrogen cycle, and manage nutrient accumulations with good husbandry...

Yet, think of the interesting results of this incredible patience! 

At the very least, try a fairly large piece of aquatic wood (or several smaller pieces, aggregated to form one large piece) some time. I think you might find this sort of arrangement quite fascinating to play with regardless of if you "prep" it in the display, or in a separate container first.

Arrange the wood in such a way as to break up the tank space and give the impression that it simply fell in naturally. Let it create barriers for fishes to swim into, and disrupt water flow patterns. Allow it to "cultivate" fungal growth and biofilms on its surfaces, and small pockets where leaves, botanicals, substrate materials, and...detritus can collect.

"Pre-populate" the system with food orgmaisms, like Daphnia, Gammarus, and the like, weeks or months before you add the fishes. Enjoy the biofilms. And select a population of fishes that can exploit the variety of new habitats that the "fallen tree" creates.

There are many distinct "zones" created by these sorts of aggregations of tree trunks and branches...This is absolutely a perfect utilization for wood. Looking at these materials from a functional perspective- observing the roles the serve and how they aggregate in Nature- then interpreting it for aquariums-is the way to go, IMHO.

So, yeah.

Trying what might appear to be a big, somewhat awkward piece of wood, or group of wood  pieces- filling much of the tank can be a challenge to our aesthetic sensibilities at first.

But guess what?

You'll get over it when you simply enjoy the setup for what it represents- not for a "typical" aquascape. And, when you populate the tank "correctly", with fishes that can utilize the interesting ecological "niches" within the tank, you'll realize that "conventional" aquascaping is not the only way...

Yes, hobbyists have been throwing big old wood pieces into tanks for decades...

However, I don't think that we've played it out in a manner that was specifically intended to replicate the "functional" aspect of them.

That is, we haven't really thought through the idea of that big, gnarly tree trunk in our tank functions not only as an aesthetic component, but more important- as an ecosystem, which supports not only an abundance of life, but provides a tremendously interesting study in adaptation and the resourcefulness of nature.

Perhaps these aggregations are a freshwater "version" of a coral reef- filled with multiple ecological niches and functions.

Oh, and they look cool, too.

Yeah, this piece covered a fair amount of territory today. And I think that it's good to look at multiple aspects of what seems liek a straightforward topic- because we as aquarists need to think beyond just the idea of utilizing wood in our aquariums. We need to think of wood as a literal "bringer of life" in both the natural habitats and in the aquarium...

It's another "mental shift" we can make. A pretty easy one, actually! 

Make it. Go for it.

So, a tree may fall in the forest..And an entire ecosystem arises. Yeah, an awful lot of good stuff starts happening underneath the water!

This is a really important thing for us to grasp.

Stay curious. Stay observant. Stay creative. Stay inspired. Stay thoughtful...

And Stay Wet.

Scott Fellman

Tannin Aquatics 


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