May 20, 2018


Lasting leaf impact...The potential of mangrove leaf litter in aquariums.

I was thinking about our world of brown water, biofilms, and algae the other day, and it hit me that, as a community, we've actually made it easier on ourselves.

In my brackish water system, as in my blackwater system, I regularly find myself topping off with new leaves. In this case, it's exclusively mangrove leaves.

The interesting thing I'm finding out about mangrove leaves is that they seem to last a very long time before completely breaking down; often two months or more in my experience.

Mangrove leaves possess specialized cell structures, including tannin cells (hello!), and sclerieds, structures within the leaf tissue which are thought to provide mechanical "support" to the leaves and discourage herbivorous predation.

Perhaps this accounts for their durability and it certainly accounts for their ability to impart color to the water via tannins over extended periods of time? Possibly. I have noticed a nice tint to my brackish water aquarium, and it's consistent with the quantity of the mangrove leaves.

I also think that mangrove leaves are a more than suitable for use in a freshwater (blackwater) systems. I use them in my home aquarium, and the tank is doing great! 

Mangroves also provide a unique ecological environment for diverse bacterial/mocrobial communities. I think the "productivity" of mangrove leaf litter beds in brackish water systems is every bit as great and important as it is in freshwater ecosystems.

In addition to bacteria, mangrove ecosystems are home to a group of fungi called “manglicolous fungi.” These organisms are vitally important to nutrient cycling in these habitats...The benefits for our closed aquatic ecosystems from these organisms are obvious! 

There is also evidence, in both brackish and marine habitats, of higher fish population densities in areas which have accumulations of decomposing leaves and mangrove materials. In several geographic locales worldwide, researchers have found a highly significant relationship between amounts of mangrove detritus and fish densities or biomass in mangrove estuaries and creeks.

Such productive habitats are naturally of interest to us as fish people. And with the ability to at least simulate some aspects of them, the time has never been better to research mangrove habitats and the functions of the leaf litter they contain, from the comfort of our own aquariums! 

So much to explore. SO much to figure out here! With all of the potential of brackish water aquariums and the use of mangrove leaves in particular, the possibilities are truly unlimited!

As we gain more an more experience in utilizing mangrove leaves in our aquariums, I believe that we may see more success with brackish water AND freshwater life forms. The unique biology which these leaves support, and the compounds they release as they break down form a basis for one of Nature's most fascinating ecological habitats.

Yeah, we're really just getting started here! 

Stay excited. Stay curious. Stay persistent. Stay creative...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

May 18, 2018


Keeping it brown instead of green...

With all of the leaves and botanicals we toss in our tanks, how do we keep those tinted microcosms from becoming algae-smothered, green water swamps?

A very good question...And you might be surprised to learn that massive algal growths in blackwater/brackish botanical-style aquariums are surprisingly uncommon, in my personal experience. Yes, despite all of the decomposing leaves, seed pods, and wood, you can still keep a botanical-style blackwater/brackish  tank clean and with minimal visible algal growths.

The keys are pretty much like those you'd expect from managing any type of aquarium, really. They're all rooted in the basics of aquarium husbandry. And the backbone of any aquarium maintenance regimen is (wait for it...) water exchanges!

I am a big one for weekly 20% water exchanges.

i have been a water exchange proponent since the dawn of my fish-keeping days, and I think it's the single most beneficial practice any hobbyist could employ to keep an aquarium healthy over the long term. In our botanical-style, blackwater aquariums, it's an essential part of the game, and should be "baked in" to our system management practices.

And of course, the source water is important- you want to use high-quality water (I'm a huge fan of RO/DI systems) to complete these exchanges. You can steep a few leaves or botanicals in the water storage containers you use, to get the "visual tint" and chemical characteristics you are looking for.

And yes, the other key ingredient for long-term success with a botanical-style blackwater/brackish aquarium is to go slowly...Stock gradually and at a lighter level than you might least in the early phases, as this gives the beneficial bacterial populations the chance to adjust to an expanding fish population and bioload of decomposing botanical materials.

I am also a huge fan of using chemical filtration media on a regular basis, not only to "scavenge" organic excesses, but to provide an extra layer of protection against the occasional lapses in husbandry that befall every hobbyist from time to time! And no, if you just use a little, you won't be removing the "tint" you're so carefully trying to cultivate- trust me. Every tank I set up has some sort of chemical filtration media, and no one could accuse me of having "clear blues-white water" in MY systems!

And of course, with fish populations comes the need to feed...and you will need to simply utilize those common careful feeding practices that you'd employ in any style of aquarium. One thought I've had about our botanical-style tanks is that they encourage fishes to graze on biofilms and yes, some of the algal films which might form on wood and other materials over time. So surprisingly, I feed my fishes a lot less frequently (like once a day) than I used to, and they're none the worse for it!

Again, stocking over a period of months before you achieve complete "fish population density" is not some high-concept thing, but I think it's so key to success. And it incorporates our mindset of patience above everything else. And everyone can do this...right?

Back to stocking for a second...this refers to both the fishes AND the botanical materials you're using in your 'scape. You don't have to start of all maxed-out with leaves and seed pods and such. 

Sure, get started with a nice selection of materials to get your tank off to a good aesthetic start, but realize that you'll no doubt "edit" both the look and "botanical population" of your tank as it evolves- as you get a feel for just how you want it to look and operate over time.

And trust me, your ideas will evolve just like your aquarium, and you'll be "editing" as you go- working the tank gradually towards some look you're trying to achieve- some environmental parameters you're wanting to give your fishes...It's part of the game here!

And you'll be regularly replacing/adding to the fish population and botanical 'populations" as they break down. And guess what? Nature will dictate the pace. Just like in everything else.

The key is to be patient...and to keenly observe what nature is "advising" you to do with your aquarium.

Common sense. Patience. Observation. Basic aquarium management skills. They're all required. Nothing earth-shattering here.

Stay patient. Stay observant. Stay consistent...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


May 16, 2018


The world beneath...some thoughts on freshwater sumps...

am a big believer in sumps.

Yes sumps.

"Seriously, Fellman....You're busy spouting reef-speak again!"

I know, you have visions of an absurdly-complicated reef system, with every possible gadget attached to the tank, costing thousands of dollars/euro/pounds, etc., while yielding only marginal performance benefits over more "conventional" freshwater filtration systems, right? 

Yeah, I hear that a lot.

First off, don't think of a sump as a "filter" in the conventional sense. Think of it as a sort of "water management system" for your display. To call it a "filter" is way too simplistic, IMHO. A sump is literally the "nexus" of your water management system- a location to take care of many of the environmental management tasks in one convenient, discreetly hidden place! 

And it doesn't need to be a byzantine maze of complexity, either.

Now, sure, reefers like them because we tend to be "gear-centric", and sumps are an excellent place to house all of the complex stuff we use to maintain our systems. That being said, sumps are excellent ways to do stuff that we don't want to do in the display. Hue? Read on...we'll get to it.

Although it can accomplish a lot of complex tasks, a sump need NOT be complex. In our context, a sump could be defined as virtually any type of container used beneath or behind an aquarium. It holds water and provides a location to place various pieces of equipment that our systems need (Yeah, even a setup consisting of a simple spare 10-gallon aquarium set up below your 50 gallon display tank to receive and process water is a "sump" by this definition).

Now, coming from a reef aquarium background, where sumps are simply the way 99% of reef systems are set up, I'm sure that it doesn't surprise you that I like them. The need to accommodate ancillary support gear like protein skimmers, reactors, etc. is just one reason why sumps have evolved into the "hub" of most reef aquarium systems, as mentioned above.

Yet, the more I play with exotic ideas in my freshwater and brackish water systems, the more I'm realizing the value of the sump, and how they can benefit freshwater hobbyists as well. I'm always surprised to see high-end freshwater setups with canister filters and reactors and such instead of sumps. Seems sort of..well, "clunky" to me. (is that like a word? "Clunky?" Whatever, right?)

Sure, we see them in some Discus tanks, African Cichlid systems, and occasionally a planted tank, yet they are the exception, rather than the rule. I'd love to see their use more widespread in the general freshwater world. Now, I realize that the breeder who keeps a hundred 5 and 10 US-gallon aquariums is unlikely to want set up a sump for each one, and the idea of a central filtration system (either incorporating a sump or some other system) is fraught with potential issues, such as transmission of disease, etc.

However, I think sumps would be a good idea for most freshwater display aquariums. I think that even modest-sized aquariums (like 40 US gallons and up) could benefit from sumps. Now, yes, there is the issue of expense and additional design considerations...You're essentially adding another little aquarium. And of course, you need to have an overflow weir, which means a "reef ready" tank (unless you want to do some retrofitting and install an overflow). And a reliable submerged or external return pump, sized properly for the system.  Yeah, a bit more work, perhaps, than simply hooking up the old Eheim... 

Then again- dealing with glassware sort of sucks, IMHO! How many have YOU broken while cleaning them? Be honest...

The advantages of this extra effort are actually numerous.

For advanced concept or speciality display tanks (like our blackwater and brackish-water systems), sumps offer extraordinary flexibility and advantages over more traditional systems, like canister filters, sponges, and outside filters. I mean, the aesthetics alone are reason to consider such an hardware visible in the aquarium is always a plus in my book. A sump allows you to place the heater, reactors, or other tech equipment conveniently out of view, yet easily accessible for access and maintenance.

That's all well and good from an aesthetic standpoint, but what other reasons would there be to use a sump in one of our systems? What are some tangible benefits? Well, to start with, I like them because they add water volume to your overall system, A typical sump (in the reef aquarium world) is anywhere from 20% to 50% or more of the volume of the display itself. And of course, this is good for a real "plus" that you can't help but consider: A sump adds volume to your overall system; volume means additional stability and biological capacity for your display. And a sump can act as a built-in "hedge" for evaporation. Sumps also facilitate Increased oxygenation. As water drains into the sump, air mixes with it, allowing for beneficial gas exchange, releasing CO2 and adding fresh O2.

(My friend Marc Levanson builds awesome custom sumps and has a great website filled with info on them..check it out)

Sumps allow you the flexibility to utilize different types of (filter) media, like botanicals/and leaves in our case, than for whatever reason, you might not want in the display tank. 

Leaves, in particular, with their associated decomposition, biofilms, and aesthetic considerations may be something that you simply don't want in your aquarium...but you might like the affect they have on the aquarium, in terms of environmental stability, cultivation of biological filtration, supplemental food sources, etc. Or maybe you want to play with live plants and not have botanicals "in situ"- or perhaps you want a "clinical" bare bottom Discus or other "concept" tank, but appreciate the "support" a sump could provide.

(I mean, you CAN really go crazy with all sorts of media in a sump if you WANT to..)

You could place botanicals, like Alder Cones, etc. into a reactor, which can conveniently be located in the sump.

And of course, with a sump, you can build in sections for the cultivation of food animals (like Daphnia or worms, etc.), creating, in effect a place in which to grow them free of predators (your fishes), feeding off of excess food and processing nutrients, with the occasional specimen getting pulled into the main display to provide a surprise "treat" for your fishes. Essentially the freshwater version of the "refugium" concept popularized by reefers years ago!

You could even light a section of the sump (on a "reverse" schedule of the display) with an inexpensive LED light to cultivate fast-growing floating or rooted bunch plants (like Water Sprite, Rotala, Hornwort, etc.) to provide pH stability for sensitive fishes, or assist with nutrient export via harvesting them. Oh, and a great "hack" for those who love nice aquatic plants but also happen to keep disruptive fishes i the display (like digging cichlids, vegetarian fishes, etc.).

These are just some of the most prominent and beneficial reasons for considering a sump for your next display aquarium. There are lots of other ideas you could play with...

Sure, you could adapt a canister to perform some of the functions (like holding "media"), or use a hang-on power filter as a sort of "moss reactor" or what not, but the concept of a sump, with it's spacious capacity and inherit flexibility gives you options and ease of operation that these "band aids" simply can't match. The ability to experiment with different "media" outside of the display is reason alone to consider one.

Even off-the-shelf "all-in-one" aquariums, with built-in rear compartments, essentially function like sumps, providing most of the same benefits as the remote units do (multiple chambers, extra water capacity, etc.).. And the possibilities are significant for these tanks, too! You can do all sorts of cool stuff with them!

The additional expense and planning that might be required when incorporating a sump into your next freshwater display will, in my opinion, easily be compensated for by the operational effectiveness and efficiencies you'll realize. 

All-in-all, sumps are a great way to give your system the "edge" it might need for long-term success and "mission flexibility" as your needs evolve or change. "kind of "future-proof", in most respects. Are they perfect for everyone? Absolutely not, as we discussed at the beginning of this piece. However, for many of us, they could open up exciting new possibilities for adventurous hobbyists with ambitious ideas...and that's kind of what we're all about, isn't it?

There's a lot going on in the world beneath our display tanks...

Stay open-minded. Stay creative. Stay innovative. Stay bold.

And Stay Wet.


Scott Fellman

Tannin Aquatics

May 15, 2018


"About those leaves of yours..."

We receive a lot of questions about all sorts of stuff, ranging from "How much does it cost to ship to__________?" to stuff like, "Will your Fishtail Palm Stems accurately represent the materials found in the jungle streams of Kalimantan, Borneo?"

You know, normal, everyday stuff.  :)

One of the more common questions we receive concerns how many leaves or other botanicals it takes, or how long it takes, to achieve a certain level of "tint" in the water, or to lower the pH by a certain amount. There seems to be a desire among many of us in the hobby to have a formula- a "recipe", if you will- to achieve a certain set of results in a certain time frame, by adding a certain amount of stuff to the water.

Can you blame us?

I mean, from the beginning of our hobby "career", we're used to instructions, rules, and products that tell us to use "X" amount per gallon/liter of water as a matter of practice, ostensibly with the goal of influencing water parameters or achieving some other results. We have come to accept these guidelines and instructions as a roadmap of sorts to achieve the results we want.

And I think that mindset of, "Just add_______" has made us a bit "soft" as hobbyists.


I think it's taken a bit of the "learning curve" out of the hobby, and made many of us expect absolutely predictable results from everything we do or add to our tanks. And as a result, when something doesn't perform absolutely as expected- or in a manner that "they" say it will- we immediately default to "This doesn't work!" or worse yet, "Something is wrong!"

And I think that's a detrimental thing.

I mean, we're dealing with living systems, chock full of variables the likes of which we may not even know for sure. Every drop of (insert favorite aquarium additive) we add to our tanks has to interact with the environmental parameters that we've set up, and those may be slightly different from the parameters in the manufacturer's test setups, or the tank of the guy down the street, or...

And that could yield different results and outcomes, thus necessitating the famous advertising line, "Your results may vary..."

Manufacturers cannot be expected to test for every possible environmental variation, filtration system, fish or plant population, etc. Rather, they base the expected results on what should be achieved by "most" hobbyists in the widest variety of generalized terms.

In other words, results just can't be 100% predictable.

Some may call this "playing it safe" on the part of aquarium manufacturers. I call it being responsible.

And besides, where is the "fun" in just following a set of instructions and procedures and POW! Instant Amazon!

Okay, fun for some, I suppose...but for geeks like me? 


Back to those leaves...

If you're adding certain leaves or botanicals to your tank, we can make only some "generalized" predictions that you're likely to see some results under "typical" aquarium circumstances. (whatever those actually are)

And even that is sort of pushing it, really.

A lot of aquarists ask us if adding a given amount of botanicals (leaves and/or seed pods) will reduce the pH of their water to some specified levels. Unfortunately, we simply can't tell you that they will, and to what level they will impact this variable. Many hobbyists may start out with hard, alkaline water and the ability of a given amount of botanicals to reduce the pH is seriously limited. I've said it numerous times, but botanicals are not capable of "softening" water.

You need an RO/DI unit to create soft water from your tap water. An investment that you have to consider and determine for yourself wether or not it's economically achievable and worthwhile for your needs.

In fact, it's actually unpredictable what specific quantities of tannins and/or other pH-influencing compounds are released into the water by a given quantity/type of botanicals, and how they will in fact, influence the pH of the water as well. Oh, and as we've mentioned before- the "tint" of the water is by no means indicative of the pH or other parameters.

And of course, there are numerous variables which may affect the ability of botanicals to influence the environmental parameters of a given aquarium.

Obviously, use of chemical filtration media, such as activated carbon, which indiscriminately removes all sorts of compounds from the water, impact this significantly. Perhaps other widely varying factors, like temperature, water movement, fish population density, substrate, etc., etc. also come into play, adding to the "grab bag" of variables!

We pretty much have to speak in generalities here!  

Yeah, sort of sounds like an excuse, but we really have no way of telling you to use "X" number of leaves or whatever per gallon to achieve a specific set of results. And no one else does, either.

Sure, we've developed our "variety packs" of botanicals with assortments of botanicals which we feel will provide "some" impact on aquariums within a rough size range, but it's a guess at best. We have to be "rugged individualists", to some extent, and do our own experimentation and develop our own "_____  leaves/botanicals per gallon" formulas, tailored to our specific aquariums.

The best recommendation we could make is to purchase/collect more botanicals than you think you'd need for a given sized aquarium. Worst case scenario here is that you'll have some extra materials to "top off" as needed.

"Gee, Scott- super helpful!"

Well, yeah, it's pretty much impossible for me to be more specific. It's simply not responsible. Perhaps one day, we will know exactly what types of tannins and humic substances should be added to a given volume of water with a given starting set of parameters in order to influence the pH by a specific range. Perhaps a true "blackwater tonic" will come to market, which has been thoroughly tested against a variety of aquarium conditions, and will offer a truly defined set of results.

In the mean time, we'll just keep adding those leaves and seed pods to our tanks, without a specific set of expectations, and testing to see how they influence our closed aquatic environments. Playing with botanicals is still more of an "art" than a science...and the opportunity to innovate and help develop "best practices" is wide open for us as hobbyists to explore.

Isn't that better than simply adding "X" number of leaves per gallon and calling it a day?

I think so.

Stay experimental. Stay bold. Stay studious. Stay open-minded. Stay disciplined...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



May 14, 2018


Similarities and saltiness...Brackish water dynamics and challenges...

As we're entering the third month of operation of our latest brackish water, botanical-style system, I've noticed some interesting things about the way this tank runs, and how it is so similar to the blackwater systems we're all familiar with by now.

Like our "conventional" (Man, that is funny to say, huh?) botanical-style systems, the brackish system embraces the same use of decomposing leaves, wood, and botanicals, with the added variables of a rich, "mud-centric" substrate and the dynamic of specific gravity to contend with. 

Interestingly, however, this type of system runs much like the blackwater, botanical-style systems that we are used to, with the exception that it is more "nutrient rich" than the blackwater tanks. The dynamics of decomposition and the ephemeral nature of leaves and such in the water are analogous in many respects, as well.

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 ate-bacterial properties. However, it's also been found that materials like humic acid, which are abundant in the mangroves, stimulate phytoplankton growth there. 

Interesting, right?

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 down the leaves further.

So, in summary, you have a very active microbial community in a brackish water aquarium. 

The management of a brackish tank is really surprisingly similar to that of a typical blackwater aquarium. The biggest difference is the salt and perhaps a greater interest in a rich substrate. Now, one parameter I changed since the system began was to increase the specific gravity from 1.004 to 1.008. This was done because it is a sort of "sweet spot" that many of the fishes which I am interested in (gobies, rainbow fishes, mollies, etc.) seem to fare quite well at this slightly higher S.G.

Also, I've made no secret about a desire at some future point to push things all the way up to like 1.021, and to incorporate corals and macro algae into the display, along with marine fishes! And, if I do execute this, the "creep" towards this higher S.G. will be made over a very long period of time (close to a year), so it will be advantageous for the resident fishes to adapt to full-strength marine water slowly. 

I have no illusions about using live Mangrove plants (available as "propugles") to serve as "nutrient export" mechanisms as they do in nature. You've seen this touted in the hobby over the years, and it's kind of silly, if you ask me. They just grow too damn slow and achieve sizes far beyond anything we could ever hope to accommodate in our home aquarium displays as full-grown plants. We've played with this idea in saltwater tanks for decades and it's really more of a novelty than a legit nutrient export mechanism.

They will, however, reach a couple of feet or so in an aquarium over a number of years, and they may be "pruned" to some extent to keep them at a "manageable" size, similar to a "bonsai" in some respects.

And of course, no brackish water aquarium is complete without brackish-water fishes...And traditionally, that has been a bit of a challenge, in terms of finding some  "different" fishes than we've previously associated with brackish aquariums. I think that this will continue to be a bit of a challenge, because some of the fishes that we want are still elusive in the hobby. New brackish-water fishes will become more readily available when the market demand is there. In the mean time, we can focus on some of the cool fishes from these habitats which are currently available to us.

However, one of the things I've found is that you need to go beyond "what the hobby articles say" and look into actual information from scientific sources about the types of habitats our target fishes actually come from. There is still a surprisingly large amount of misinformation about there concerning fishes long thought to be "brackish", when the reality is that they are often found predominantly in non-brackish habitats, with perhaps only isolated populations of fishes being brackish fishes.


There is still much to learn; much to dismiss as incorrect or unnecessary, and a lot of technique still to develop...

Isn't that fun!

Stay intrigued. Stay creative. Stay engaged...

And Stay Wet.


Scott Fellman

Tannin Aquatics  

May 13, 2018


"Cyclical clarity" and other botanical quirks...

Ever noticed that aquariums seem to go in "cycles", and display certain "quirks" in their function?

For example, some tanks will enjoy periods of time where the fish and plants are actively growing, the water is crystal clear, unwanted algal growth is minimal, and everything seems to be "spot on."

And then, inexplicably, after months or years, the tank may not look quite as good for several weeks, only to rebound to it's former glory with minimal intervention on your part.

I think we've experienced this in planted tanks. 

And more recently, I've experienced certain "quirks" with blackwater/brackish botanical-stye aquariums. 

In particular, once of the things I've noticed is that the water will take on a bit of "cloudiness" from time to time, almost as if it's been "dosed" with some sort of materials which make it a bit turbid- even with excellent husbandry techniques.

And in a sense, it has. I think there are a few explanations, once of which is that there is a gradual, yet cumulative decomposition of organic materials from within the botanicals themselves; maybe it's substances within the wood or botanicals you're playing with, like lignin, etc., which seeps into the water column as the materials break down, exposing new layers of their tissues to the aquatic environment.

And then it goes away just as mysteriously as it comes...

And of course, as a lifelong aquarium hobbyist, when you see stuff like cloudiness, you first start looking at overall water quality, feeding, and husbandry technique. I am a fanatic water quality guy, being a reefer,  and am a devoted tester and water exchange person. Yes, is it possible that my feeding or technique could have caused this? Maybe, but not likely. My tanks are environmentally stable, have little to no detectable nitrate, barely detectable phosphate, and receive regular water exchanges.

And I stock lightly.

However, arrogance aside- it IS Possible, right?

The other would be that there is a sort of "bacterial bloom", which is certainly possible. Interestingly, I utilize mangrove wood in both my home blackwater and brackish water aquariums at this time and I'm of the belief that this is a beautiful type of wood, but it's very "dirty" from a standpoint of materials contained within the tissues of the wood. Both of my tanks experienced an initial "haziness", which I hadn't seen to the same extent with other botanical systems I've played with which utilized different types of wood.

Coincidence? Perhaps.

I mean, every botanical tank seems to get a certain "patina" to it (one of my blackwater-enthusiast friends calls it "flavor") which impacts the overall appearance of the system. And we do throw seed pods, leaves and other stuff into our tanks- a perfect "cocktail" for unusual water conditions, huh?

Ultimately, the cloudiness thing just sort of goes away, yielding that sparkling brown clarity that we love. Sure, some activated carbon and stuff like Poly Filter help, but I think the biggest  factor is time.

The other random factor in our version of the botanical-style brackish aquarium is the use of very rich, mud-influenced soils in the composition of the substrate we play with. I think some of the material leaches into the water column on occasion. Add this to the equation, and with the occasional burrowing activities of the snails we employ, and with the significant water movement provided by electronic pumps, and this is another factor which can affect water clarity.

And perhaps it's also the including of the mangroves themselves, and the epiphytic organisms which live on and among their roots and propagule structures?

The other quirks we all experience from time to time is the accumulation and dissipation of biofilms and occasional biocover on our botanicals. I know many hobbyists (myself included) which have run tanks with minimal biofilm over their botanicals at almost every phase of the tanks existence.  

Others have experienced the (scary to the uninitiated) burst of biofilm which accompanies the addition of botanicals to a new aquarium. In our community, we take the waxing and waning of biofilms in our tanks as a sort of "right of passage", and have come to expect and tolerate the stuff. It was, and still is- a big part of the mental shift hobbyists have to make when transitioning to this type of aquarium from a more "conventional" one.

Accepting that decomposition, change, and the transformations of hardscape materials by fungal and bacterial action are simply part of the game, and as you're tank matures and becomes more biodiverse, it "evolves" to some extent.

Oh, but that biofilm and turf algae and fungal growth really gets to some people!

Left alone, it almost always seems to dissipate in just a few weeks. And occasionally, you'll see a covering of biofilm or turf algae crop up on botanicals which have been submerged for some period of time, seemingly without reason. 

These occasional "outbursts" by the biofilms may disappear as quickly and mysteriously as they appear, without any apparent correlation. Or do they? Well, there must be SOME explanation! 

And of course, as we know, everything occurs in nature (and our tanks) for a reason...And the searching for answers and trying to figure out the "hows and whys" of our unique aquariums has been a real delight for me.

Nature- and out tanks...are ruled by cycles. Seasonal? Biological? All types. Something we haven't thought a lot about in aquarium keeping (except for the nitrogen cycle, of course). 

Cycles and quirks.

The undeniable "quirkiness" of a blackwater/brackish, botanical-style system is one of the most enjoyable facets of this type of approach. It's a constant evolution and a tremendous thing to witness firsthand.

Yes, they're filled with quirks. However, botanical-style aquariums are filled with a certain something..A "mystery", a "vibe", an operational "structure", which separates them from what we have come to expect as "normal" for aquariums over the decades...

And that "something" is what keeps many of us coming back for more- quirks and all!

Stay excited. Stay devoted. Stay experimental. Stay creative. Stay patient...

And Stay Wet.


Scott Fellman

Tannin nAquatics 


May 11, 2018


Radical moves...Or subtle iterations?

Have you ever done a radical change on an already established aquarium?

You know, the one that was going to be the Apistogramma biotope tank and it suddenly evolved into a wild livebearer tank, or the African cichlid tank that mutated into a brackish water aquarium?  

Stuff like that?

I was thinking about this the other day when I was doing a water change on my blackwater aquarium. I was thinking to myself, "Man, it would be so easy to turn this characin-dominated Amazonina-region-themed tank into a tank into an Asian-themed tank. A few little tweaks, and..."

I almost just went for it...

Sometimes it's thinking about a fish that does it...Or seeing a pic from nature, or the work of a fellow fish geek.

It inspires me to edit or even wet to do a wholesale change...Most of the time, I simply "edit" what I have to "scratch the itch"...

Yeah, "editing" is pretty easy. A little movement of the wood stack...a change in the orientation of some botanicals...shifting sand around a bit. Stuff like that.


However, what about when you're thinking about, for example- one blackwater habitat for another- from a different part of the world, for example. How is it when you do something really radically different, like switching from one environment to another?

Ever done that?

I've had times when I just woke up and turned a tank on end into something totally different...

And it worked out pretty well, actually...But it's almost a "shock-trauma" of sorts...One minute it's leaf litter and Manzanita, the next minute your tank is filled with Mopani and Palm fronds....

Yeah, I did that...

And it's kind of fun, too...Just doing different stuff on the spur of the moment...I love that sort of thing. It prompts a sort of spontaneous creativity that is a distinct departure from our uber-patient typical selves, right?

On the other hand, the better way to go is simply to set up another tank, right? Of course, that assumes a few things, doesn't it?

And of course, that's how "Multiple Tank Syndrome" starts...

A dangerous though for a weekend, huh?

Stay creative. Stay engaged. Stay excited. Stay inspired...

And Stay Wet.


Scott Fellman

Tannin Aquatics 




May 10, 2018


Function. Form. Aquascaping. Fishes.

Ever thought about this?

Hobbyists put this huge amount of time and energy into trying to achieve a perfect "natural-looking" placement for wood and other hardscape materials in our aquariums   when the reality is that, in nature, it's decidedly random- based upon forces such as weather, current, water depth, substrate composition, etc. Things which, although might have some degree of predictability (i.e.; tides or seasonal rains) may have unpredictable effects on the aquatic habitats.


Yet, we collectively spend many hours as fish geeks in the pursuit of "natural looking", while applying high-level artistic technique and tradecraft to our work. Nothing wrong with that, IMHO. I mean sure, it's an enjoyable pursuit for many, but I find this delicious irony in the fact that we've created such a set of "rules" and "practices" on how to create our interpretations on a natural-looking aquatic habitat.

I'd just like to see us apply the same level of dedication to really understanding and replicating the "function" of nature in relation to its appearance, and embracing the random nature of its structure.

Is there not also beauty in "randomness", despite our near-obsessive pursuit of rules, such as "golden ratio", color aggregating, etc? Just because last year's big 'scaping contest winner had the "perfect" orientation, ratios, and alignment of the (insert this year's trendiest wood here) branch within the tank, doesn't mean it's a real representation of the natural functionality of "randomness." 

In other words, just because it looks good, it doesn't mean it's what nature looks like.

And ask yourself, honestly- isn't this what aquarists like Amano were really trying to stress, rather than preaching the rigid adherence to some "formula" of hardscape placement? Could we be placing too much emphasis on the practice of embracing rigid rules of Iwagumi rock placement, and not enough on stuff like the philosophy of "Wabi-Sabi"- a celebration of the transience of nature- which, IMHO represents Amano's greatest gift to the hobby?

Can't you see the beauty in replicating scenes like this one, rather than just last year's high-placing competition diorama scape?

Any random stream in nature contains inspiration and ideas which we can apply to our aquascapes, without having to overthink it. Sure, even the simple act of placing a piece of wood in our tanks requires some consideration...

However, it think a lot of it boils down to what we are placing the emphasis on. Perhaps it's less about perfect placement of materials for artistic purposes, and more about placing materials to facilitate more natural function and interactions between fishes and their environment.

With the really great variety of wood available these days to the everyday hobbyist, I'd dare make the almost "heretical" assertion that you can pretty much grab virtually any decent piece, or pieces- of of wood and create an incredibly satisfying, natural-looking scape. "Functional aquascaping" is as satisfying as any other form, IMHO.

Another major consideration with driftwood in our aquascapes is perhaps even more important than anything else, in my opinion: The "recruitment" of organisms (algae, biofilms, plants, etc.) in, on, and among the matrix of wood structures we create, and the "integration" of the wood into other "soft components" of the aquascape- leaves and botanicals.

This is an area that has been worked on by hobbyists rather infrequently over the years- mainly by biotope-lovers. However, embracing the "mental shift" we've talekd about so much here- simply allowing the growth of beneficial biocover, decomposition, tinted water, etc.- is, in our opinion, the "portal" to unlocking the many secrets of nature in the aquarium.

We don't really have to execute on this part...nature takes over.

The knowledge that we as aquarium hobbyists gain by researching, replicating, and maintaining systems that are a more realistic functional representation of nature is priceless. Unlocking the secrets of fish interactions, composition of the population, and parameters of the environment itself is key to spawning and maintaining numerous species of fishes, so that future generations may enjoy them in the wild.

So, my thinking is that we should ask ourselves why the wild aquatic environments look the way they do, and how they function. We can formulate new ways to replicate them, and to create sustainable aquarium habitats for the fishes that we treasure so much. I believe that we shouldn't over-think the "look" as much as we consider the functions of the work we're creating.

And the big winners? The fishes. The natural habitat. And the hobby.

Not bad.

Stay bold. Stay creative. Stay inspired. Stay excited...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

May 09, 2018

1 comment

Talking "dirty..."

Recently, we did an informal poll on our Facebook community page, asking our community members if they leave their botanicals and leaves in their aquariums until they completely break down, or if they remove them as soon as they start to decompose. The results showed that an astounding 93% of hobbyists tend to leave them in until they completely break down!

This is an extraordinary example of a mind-set shift in the way aquarists think about how we manage our aquariums- and even more important- in what we view as aesthetically and biologically acceptable. 

For many, many years in the hobby- and for a fairly long time in my personal hobby "practice", I was a big fan of "pristine, sparkling, and spotless" aquariums. I am not sure how this came about, except perhaps because we were indoctrinated from the earliest days in our hobby, and throughout the decades that an aquarium must be maintained in a nearly "sterile" condition. Photos of many aquascaping compositions were almost always of spotless aquariums, perfectly manicured. Beautiful, but not all that realistic in many cases.

In my opinion, the only time you'd see a more "realistic-looking" aquarium was when you'd see a biotope aquarium, representing a specific niche. Now, these are often highly researched, rigorously disciplined systems, but perhaps the high level of authenticity which many biotope enthusiasts hold themselves to makes working with the even "too thorough" for many hobbyists to want to play with. 

And there is a sort of "happy medium" out there, isn't there? A middle ground between the typical "sanitized" aquarium and the higher-concept biotope aquarium...

I sort of evolved my own view of this after many years of researching and observing the natural aquatic habitats, then reconciling between them and what I hoped to accomplish in the aquariums I created.

With the advent of our blackwater/brackish, botanical-style aquariums, we're seeing an acceptance of the appearance and the value of this approach. The idea of some leaves and botanicals breaking down in our aquariums doesn't really seem "dirty"...rather, we prefer to classify it as "natural."

And that's what it's really all about, right? More completely embracing and replicating nature in ways not previously considered "acceptable" to many hobbyists. 

And then, there are those "functional" aspects...

One of the things that I have personally noticed in every botanical-style aquarium which I have managed is the they run with essentially undetectable levels of nitrate and phosphate (the two most commonly accepted measures of water quality for most hobbyists) during their entire existence.

This is interesting, because, after all, we're talking about aquariums filled with decomposing leaves and other botanical materials. You'd think, by "aquarium parlance", that this would constitute "dirty" conditions, right? How could it be, then, that myself and others experience such high water quality in these types of systems?

Well, sure, some of it could be attributed to the typical tenants of good aquarium husbandry: Application of regular water exchanges, appropriate stocking levels, and careful feeding. Yet, I theorize that the greater contributor to high water quality in these botanical-style systems is the population of bacteria, fungi, and other beneficial microorganisms, which benefit from an available "carbon source" (i.e.; leaves and such) and, through their normal processes, reduce the levels of detrimental substances in the closed ecosystem of an aquarium.

Much in the way plastic polymer "bio-pellets" have been employed by some in the reef aquarium word to foster the growth and function of beneficial bacteria- I think our use of botanicals accomplishes the same thing in our aquariums. Indeed, when I reflect on the numerous (expensive) products, like substrate additives and bacterial products, which many planted aquarium enthusiasts employ to foster good conditions for aquatic plants, I can't help but think that we're doing much the same- perhaps unintentionally, and with more of a "shotgun approach"-when we allow botanicals to completely break down and mineralize in our substrates.

Now, I think that a lot of the reactions and such are "above my pay grade", in terms of describing the specific biochemical processes which are occurring...I'm not a biochemist, so much of my theorizing here would be better confirmed by those with the appropriate background. My experiences, however, lead me to believe that something interesting is happening that benefits our aquariums, and is worthy of further research.

So, what we consider "dirty", in terms of aesthetics and appearance, might just be the most beautiful aquariums we've ever seen.

Something to think about on a Wednesday...

Stay curious. Stay bold. Stay excited. Stay thoughtful...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


May 08, 2018


What's next?

The other day, I  took a longer-than-usual amount of time to sift through my Instagram feed, which of course, is littered with aquarium people, specifically, those who do aquascaping, biotope aquariums, etc.- stuff that's "right up my alley", as they say. 

As I looked at the posts, I saw many amazing things, ranging from the most base ("Buy our product!") to the work of amazing aquascaper-phlilosopher-types showing a pic of a single rock or twig in a cube-shaped tank, pondering "What's next?"

What IS next?

What's the next thing we're going to do in the hobby?

What's the next "big breakthrough" that will be made? Will it be breeding that previously "impossible" fish? Will it be the creation of a new aquascape that inspires a generation? Or will it simply be a progression of things that make the hobby easier for all of us?

If you look at the "high concept" aquascaping world, it becomes obvious that the "next big thing" is definitely some evolution of the layout of an aquarium. Some different way of arranging rock, wood, and plants in a way that captures both our aesthetic sensibilities and our need to create living art in a way not previously attempted. A way to distill nature into something abstract, yet pragmatic. Perhaps still under Amano's shadow, but searching for its own identity, the aquascaping world moves ever forward.

If you look at the "mainstream hobby" world, it's definitely about acquiring and breeding new species of fishes...about reproducing and making more commonly available fishes which were previously considered too difficult to persuade to reproduce in our tanks. I think it has been for some time, and will continue to be. And that's never a bad thing. 

In the reef aquarium world, it's this never-ending quest to achieve...something...with that next piece of high-tech gear or revision of husbandry, the hopes of the hobby's futures are pinned to attaining something different than what we are achieving now...maybe its spawning coral. Maybe it's simply acquiring different stuff...I suppose I'm deeply critical of this world, having devoted much of my life to it in the past couple of decades. I think the jury's still out on this one.

And of course, my mind moved on to what we do here...

In our world of blackwater, decomposing botanicals, and more natural vibes, what is the next "breakthrough?" 

IS there a "breakthrough?" 

I don't think so.

Rather, I think what we'll be seeing is progression. I think that the initial "breakthrough" has been simply the more popular acceptance of the blackwater/botanical style aquarium. That "mental shift" we've spoken about so often here.

When you take out the part about us "accepting the aesthetic" and the impact on the aquatic environment, it's simply about execution. We are in a phase now where the previously "freak-show" classification has been removed from blackwater aquariums, and they're now more popularly seen simply as another approach to aquarium keeping.

I think we are not seeing a particular "breakthrough" of any sort; Rather, the entire concept of playing with botanicals and blackwater aquariums is really a sort of "evolution" of sorts...a type of change to our mindset. And a learning of technique. Validating theories we might have had about stuff...or proving them invalid, as the case may be.

We are understanding the "capabilities" of botanicals, and how they impact the water chemistry. We're educating ourselves and reminding each other that they can't "soften" water, but they do have impact upon the pH and TDS of our systems. I'm not certain how this idea emerged. This is a big "mental hurdle" for a lot of hobbyists. Overcoming the perception that just tossing in some Catappa leaves or other botanicals into the aquarium will somehow "soften" hard water is a real "thing" that a lot of people have had in their heads for some reason! It's been a "mission" of sorts for me to help change this misconception...In the process, I think I've convinced a lot of enthusiasts to purchase RO/DI units over the years, lol! (RO manufacturers, please send your royalty checks to me...)

I think we're in an "execution" phase, getting to understand the regular workings of blackwater/brackish botanical-style aquariums- understanding the processes which occur in our tanks, and how they impact our fishes.

We have so much to learn. 

I mean, sure, we know all about the tinted water...we know generally what tannins are and how they are present in water...However, we don't even know which of any dozens of possible tannins that the leaves, wood, and botanical materials we use produce, and which ones are found in the natural habitats we obsess over.


Gallic acid? Phloroglucinol? Flavins? Chlorogenic acids? Ipecaucuanic acids? Perhaps its enough to just have "tannins" in the water! However, perhaps the next evolution will involve specific types/classes of tannins produced by botanicals. What if we find out that specific tannins from specific plant materials influence fish health, color, or reproduction in specific ways?

Will that constitute a breakthrough? Or just an evolution in our understanding? Will it even be important, in the grand scheme of things? Will the mid 21st century commercial "blackwater extracts" actually be specific types of tannins and other substances derived or synthesized from botanicals from various materials found in the natural environments of our fishes, rather than just boiled bark and such? "Targeted" materials, rather than just a "brew" of assorted botanical extracts of as yet undetermined origin or effectiveness?

Are we still "shooting from the hip" throwing in various leaves and botanicals and sort of "impacting" our closed aquatic habitat in a sort of generic manner, not really 100% certain if what we're adding is effective or not at achieving our desired goals? Just thinking to ourselves that if the water is brown like it is in The Amazon, something good is happening?

I think so. I mean, we've come along way- but we have a long, long way to go until we really have a serious understanding of this stuff, and how to use it in the most optimum and efficient manner in our aquariums. Reminds me a bit of the first attempts at making synthetic saltwater. It's not simply a matter f throwing in some various salts and major/minor ions and POW! You've got a reef environment. Rather, there are trace elements, organic materials, etc. to consider... A real "thing" to understand. 

Pretty exciting, really. From an aesthetic, environmental, and even commercial standpoint.

And we haven't really done ANYTHING yet on botanical-style, tinted brackish water aquariums...a whole new thing to play with.

As far as I'm concerned, our real understanding of the whole blackwater, botanical-style aquarium specialty is in its infancy, really. I know, hobbyists have been playing with "blackwater aquariums" for decades; however, I think it has only been very recently that they've been viewed as more of an "approach" to maintaining fishes than they have as simply an unusual novelty of sorts. What's been fueling the growth is not just a fascination with the aesthetics, but a desire to understand the tangible benefits to our fishes. A desire to recreate a natural habitat. And a longing to do better than we have in the past.

Another evolution, really.

We're still at that exciting phase where we are working out the "hows and whys" of all of this stuff. We have many essential "best practices" more-or-less agreed upon, such as the idea of preparation of botanicals. We're digging the funky aesthetics...We have the mindset of going slowly, monitoring water chemistry, and studying carefully the impact of everything we add into our closed aquatic environments. Of all of the things we do in our niche, perhaps what I'm proud of the most is that for our community, it's not simply "dump and pray" botanicals...Rather, it's study, prepare, plan, measure, observe, and adjust. Those who become part of our "tribe" know this, and impart this stuff to newcomers. 


What I find equally interesting is how we are seeing more and more hobbyists who breed fishes of various types (which come from blackwater habitats in nature) under more natural conditions provided by use of botanicals. Now, again, this is not a "new thing"- environmental manipulation. However, it is a sort of acceptance that the use of botanicals and such to create conditions optimal for certain fishes to thrive and reproduce in is a good way to go. A sort of realization that yes- the stuff works for this purpose.

What's next in our botanical world? 

Refinement. Assessment. Adjustment. Study. Application. Failures. Successes. Understanding...

And each and every one of us is contributing to the body of knowledge that is the blackwater botanical world. 

Yes- we're ALL part of "what's next."

Isn't that exciting?

Stay engaged. Stay excited. Stay curious. Stay honest. Stay creative...

And Stay Wet.


Scott Fellman

Tannin Aquatics 







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