May 28, 2020


Stocking "in sequence?" An approach to creating more natural aquariums...

The idea of an "aquarium as a microcosm" is not exactly a new concept. However, the idea of setting up an aquarium to provide more than just a physical "shelter" for its inhabitants; but rather, as a functional habitat designed to create a small ecosystem, and an "in situ" food culturing system intrigues me.

And it kind of goes back to looking at natural aquatic systems.

If you're like me, you spend a little too much time pondering all sorts of arcane aspects of the hobby...Okay, so maybe you're NOT like me, but you have a rather keen interest in the way Nature operates in the wild aquatic systems of the world.

As one who studies a lot of details about some of the habitats from which our fishes come, I can't help but occasionally wonder exactly what it is that brings fishes to a given location or niche within a environment?

Now, the first answer we're likely to proffer is the most apparent...right? I mean, they follow the food!

Fishes tend to move into new areas in search suitable food sources as part of their life cycle. And food sources often become available in habitats such as flooded forest areas after the rains come, when decomposing leaves and botanical materials begin to create (or re-activate, as the case may be) "food webs", attracting ever more complex life forms into the area.

In the case of many blackwater, leaf-litter habitats in South America, for example, the whole food web starts with our old friends, fungi and bacteria. In fact, it's been postulated by scientists that the food web depends primarily on the litter and its associated decomposing fungi. From there, sponges, rotifers, and amoeba arise, and are in turn fed upon by "specialist feeders", such as shrimps (yeah, there ARE shrimps in Amazonia!) and detritivorous fishes.

Then, of course, you also have inesect larvae, particularly chrinomods (i.e.; bloodworms- larval "flies"), and small crustaceans such as Daphnia and the like, which are preyed upon by a host of fishes.

And of course, flooded forest areas are also attractive to fishes which consume the very fruits, plant parts, and terrestrial insects- "allochthonous inputs" -materials imported into an ecosystem from outside of it.  As more materials fall from the trees and surrounding dry areas, the greater the abundance of fishes and other aquatic animals which utilize them is found.

These materials will continue to fall into the water and accumulate throughout the period of inundation, maintaining the richness of the habitat as others decompose or are acted on by the organisms residing in the water. And of course, these materials continue to provide foraging for fishes for the duration of this period of time.

So, how does this relate to stocking an aquarium? Is this something we can interpret and utilize in our aquarium designs?

Well, for one thing, I think that you could literally create a sort of "sequence" to stocking various types of fishes based on the stage of "evolution" that your aquarium is in, although the sequence might be a bit different than Nature in some cases. For example, in a more-or-less brand new aquarium, analogous in this case to a newly-inundated forest floor, their might be a lot less in the way of lower life forms, such as fungi and bacteria, until the materials begin breaking down. You'd simply have an aggregation of fresh leaves, twigs, seed pods, soils, etc. in the habitat.

So, if anything, you're likely to see fishes which are much more dependent upon the aforementioned allochthonous from the terrestrial environment. This is a compelling way to stock an aquarium, I think. Especially aquarium systems like ours which make use of these materials en masse.

Right from the start (after cycling, of course!), it would not be unrealistic to add fishes which feed on terrestrial fruits and botanical materials, such as Colossoma, Arowanna, Metynis, etc. Fishes which, for most aquarists of course, are utterly impractical to keep because of their large adult size and/or need for physical space!

(Pacu! Image by Rufus46, used under CC BY-SA 3.0)

Now, a lot of smaller, more "aquarium suited" fishes will also pick at these fruits and seeds, so you're not totally stuck with the big brutes! Interestingly, the consumption and elimination of fruits by fishes is thought to be a major factor in the distribution of many plants in the region.

Do a little research here and you might be quite surprised about who consumes what in these habitats!

More realistically for most aquarists, I'd think that you could easily stock first with fishes like surface-dwelling (or near surface-dwelling) species, like hatchetfishes and some Pencilfishes, which are largely dependent upon terrestrial insects such as flies and ants, in Nature. In other words, they tend to "forage" or "graze" little, and are more opportunistic, taking advantage of careless insects which end up in the water of these newly-inundated environs.

I've read studies where almost 100 species were documented which feed near-exclusively on insects and arthropods from terrestrial sources in these habitats! If you dive a bit deeper than the typical hobbyist writings, and venture into scholarly materials and species descriptions, you'll be fascinated to read about the gut-content analysis of fishes, because they give you a tremendous insight about what to feed in the aquarium!

Continuing on, it's easy to see that, as the environments evolve, so does the fish population. And the possibilities for simulating this in the aquarium are many and interesting!

Later, as materials start to decompose and are acted on by fungi and bacteria, you could conceivably add more of the "grazing" type fishes, such as Plecos, small Corydoras, Headstanders, etc. As the tank ages and breaks in more, this would be analogous to the period of time when micro-crustaceans and aquatic insects are present in greater numbers, and you'd be inclined to see more of the "micropredators" like characins, and ultimately, small cichlids.

Interestingly, scientists have postulated that evolution favored small fishes like characins in these environments, because they are more efficient at capturing small terrestrial insects and spiders in these flooded forests than the larger fishes are!

And it makes a lot of sense, if you look at it strictly from a "density/variety" standpoint- lots of characins call these habitats home!

Then there are detritivores.

The detrivorus fishes remove large quantities of this material from submerged trees, branches, etc. Now, you might be surprised to learn that, in the wild, the gut-content analysis of almost every fish indicates that they consume organic detritus to some extent! And it makes sense...They work with the food sources that are available to them!

At different times of the year, different food sources are easier to obtain.

And, of course, all of the fishes which live in these habitats contribute to the surrounding forests by "recycling" nutrients locked up in the detritus. This is thought by ecologists to be especially important in blackwater inundated forests and meadows in areas like The Pantanal, because of the long periods of inundation and the nutrient-poor soils as a result of the slow decomposition rates.

All of this is actually very easy to replicate, to a certain extent, when stocking our aquaria. Why would you stock in this sort of sequence, when you're likely not relying on decomposing botanicals and leaves and the fungal and microbial life associated with them as your primary food source?

Well, you likely wouldn't be...However, what about the way that the fishes, when introduced at the appropriate "phase" in the tank's life cycle- adapt to the tank? Wouldn't the fishes take advantage of these materials as a supplement to the prepared foods that you're feeding them? Doesn't this impact the fishes' genetic "programming" in some fashion? Can it activate some health benefits, behaviors, etc?

In other words- are they more "comfortable" because of some long-established internal "programming", which provides them with a certain degree of "well-being", if you will, knowing that minimal competition or predators are about? Do they behave differently, acclimate to captivity faster...feed better, have more robust overall health and resistance to disease? 

Do these conditions help initiate spawning behavior more readily? 

Interesting to ponder, huh?

These are purely speculative, but they can give you some examples of things that we could unlock when we think about how the natural habitats become populated following seasonal and other environmental changes and evolutions. Studying these changes and the conditions which create them is a fascinating educational process that we should all embrace!

The idea of "meeting your tank where it is" and working to stock it and manage it based on what phase of its existence in is fascinating to me. Now, it's not new to add fishes in a sequence or whatever...yet I believe it IS an evolution in the process when we look at stocking in the context of how the environment we're trying to replicate evolves and hosts fishes.

It's sort of another way of looking at many aspects of our aquaria differently- such as providing environmental parameters appropriate for the fishes we like, to aquascaping based on the physical needs of the fishes and the environmental niches from which they come. Not simply "aquascaping" an aquarium, then adding the fishes to compliment it.

I'm thinking about looking at a natural habitat and asking yourself to consider why it looks the way it does, and why the specific fishes which reside there are present. Asking yourself what makes them live there?

How fishes "follow the food" is just one example of this process.

There are, of course, other reasons besides food. There may be environmental reasons. Adaptations to tidal influxes (I'm thinking of brackish habitats), the need to seek out specific conditions in which to spawn. Freedom from predators...particularly for juvenile fishes.

Of course, I'm thinking about mangrove estuaries and seagrass beds, where many larval fishes go to feed and grow before heading out to sea or other habitats...but there are numerous other examples in various niches...

So many possibilities. There are so many ways to develop aquariums and stock them based simply on looking at Nature.

Meet your aquarium where it is.

Set the stage for the life forms you want to keep by considering exactly what brings them there in Nature...then observe, enjoy, and learn.

Stay observant. Stay inspired. Stay curious. Stay intrigued. Stay objective. Stay patient...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


May 26, 2020


Water, soil, weather, fishes...

Have you very thought about how water reaches all of the wild aquatic systems of the world? I mean, it's got to get there some way, right? So, how does it reach the ponds, lakes, streams, and rivers and forest floors of the world?

Well, some simply falls into the body of water directly from the sky, and that's that. Some is a result of other overflowing streams and rivers (like, ya' know- those flooded Igapo forests we talk about!). Inputs of precipitation falling over the area of an aquatic habitat are transferred to the habitat via a number of different pathways.

It's surprisingly complicated.

There's like a whole field of science devoted to studying this process! It's called Hydrology, and it's incredibly interesting...As fish geeks, we're probably already acquainted with this field of study, at least tangentially! 

So, water comes from a variety of sources, reaching a myriad of ecological niches. However, not all of the water has such an easy journey on its way into our favorite aquatic habitat!

Even in the case of rainwater, some of it simply lands on tree leaves in the surrounding area and evaporates. This is a process scientists call "interception", and accounts for the fact that not all water makes it to the ground. Water that does reach the ground enters the soil through a process called infiltration. slowly percolating down to soil areas known as the "saturated zone"- and as you'd imagine, this is where the fun really begins! (to a soil geologist, at least!)

The soil properties control the infiltration capacity; these include things like soil permeability, the presence of vegetation and plant roots, and how much water is already in the soil. Through what is known as "ground water flow", ultimately, the water finds it way into our favorite aquatic habitats. It's important to note that soil texture ( the relative proportion of sand, silt and clay particles within the mix) affects infiltration rates. 

Sandy soils like the "podzols", common to forested areas of South America that we've talked about have higher permeability than some clay-based soils. In some really arid areas a "crust" can form on the soil surface, decreasing the permeability. And of course, the thickness of the soil directly affects how much water the soil can actually absorb.

And, in many cases, the substrate composition and its relationship with water has direct impact on the life forms which inhabit these aquatic systems. In the case of some habitats, like vernal pools, which are filled with water seasonally, the substrate is of critical importance to the aquatic life forms which reside there.

Let's talk killies for a second!  One study of the much-loved African genus Nothobranchius indicated that the soils are "the primary drivers of habitat suitability" for these fish, and that the eggs can only survive the embryonic period and develop in specific soil types containing alkaline clay minerals, known as "smectites", which create the proper soil conditions for this in desiccated pool substrates.

The resulting "mud-rich" substrate in these pools has a low degree of permeability, which enables water to remain in a given vernal pool even after the surrounding water table may have receded! And, of course, a lot of decaying materials, like plant parts and leaf litter is present in the water, which would impact the pH and other characteristics of the aquatic habitat.

Interestingly, it is known by ecologists that the water in these pools may stay alkaline despite all of this stuff, because of the buffering capacity of the alkaline clay present in the sediments!

And, to literally "cap it off"- if this impermeable layer were not present, the vernal pools would desiccate too rapidly to permit the critical early phases of embryonic development of the Nothobranchius eggs to occur.

Yes, these fishes are tied intimately to their aquatic environment.

(Image by Andrew Bogott, used under CC BY-S.A. 4.0)

The fascinating concept of embryonic diapause ( a form of prolonged, yet reversible developmental arrest) is well-known to scientists and lovers of annual killies. The occurrence and length of time of diapause varies from species to species, yet is considered by scientists to be an evolutionary adaptation and ecological trait in various populations of Nothobranchius, tied directly into the characteristics of the ephemeral habitats in which these fish reside!

So, yeah- the relationship between water and soil is actually a remarkably complex one, with biological implications that we probably haven't thought about very much as hobbyists. Studying how water gets to the aquatic habitats- how it creates them- is a critical key to understanding the needs, behaviors, and adaptations of our fishes!

During that journey into the (aquatic) habitats, materials like humic substances, minerals, etc. will be absorbed into the water from the surrounding soil. Yeah...that's the interesting part: The surrounding geography and geology have as much to do with the ultimate water characteristics as anything else! Like so many things in Nature, everything is somehow interrelated!

Once again, bringing it all back to a more practical aquarium point of view, I can't help but wonder if working with different types of substrate materials (soils, sands, etc.) in our "makeup water" containers could yield some similar effects to those we see when we steep leaves and botanicals in the water. Could the right combination of soils in both our makeup water containers and even in the aquarium create even more realistic water conditions for our fishes and aquatic plants?

One can only wonder...

It makes a ton of sense.

We're seeing more and more specialized "aquatic soils" for plants which are designed to simulate some of the natural habitats in which they are found. Well, fishes are typically found in those habitats, too, right?

Why should the plants have all the fun?

Wouldn't it make sense to utilize some of these specialty substrates, or substrates comprised of some of these components in tanks which feature fishes and not just plants (or even devoid of plants?). What potential benefits for our fishes could be gained by using these more "technical" aquatic plant substrates in our fish-centric botanical-style blackwater aquariums? 

We're sure as hell going to try to find out! The "Nature Base" line of specialized premium substrates is going to debut soon, and we think it just might change the way we think about substrates in the hobby.

Like, we're busy designing aquatic displays around the substrate, and its form and function...

Stay tuned for way more on this later this summer!

And one more thing to erstwhile copycats of the Tannin brand, of which there have been a few:

"In order to be irreplaceable, one must always be different..." - Coco Chanel

Like I've alluded to previously- it's gonna get real weird real soon. Too many vendors are getting into the botanical game, slinging leaves and pods and just sort of "commoditizing" the whole thing- and that's a sure sign that it's time for Tannin to push beyond...Let's just say that we're going to go WAY beyond, in ways we're pretty confident that no one else in the hobby/industry has- and leave it at that for now... 

Oaky, commercial plug and micro-rant/warning aside, let's dive back in to the topic at hand...

With water finding its way into the streams, rivers and other areas from so many sources, there is probably so much we can learn from finding out more about the surrounding areas  themselves, and how water ultimately makes it into the bodies of water we are so obsessed with. This is an area of study in the hobby that's really wide open for advancement, IMHO.

The possibilities are endless here!

In a blackwater environment, the color is a visual indicator of an influx of dissolved materials that contribute to the "richness" of the environment. Indeed, a blackwater environment is typically described as an aquatic system in which vegetation decays, creating  tannins that leach into the water, making a transparent, acidic water that is darkly stained, resembling tea.

Despite the appearance, as a general rule, blackwater rivers are lower in nutrients than clear rivers. They have very low concentrations of major ions, such as sodium, magnesium, potassium, and calcium, and lower conductivity and typically low levels of dissolved solids. Think about what that means for just a second, and about the many factors that influence the water characteristics of these unique habitats.

Wouldn't it be interesting, when contemplating more natural biotope/biotype aquariums, to study and take into consideration the surrounding geology and physical characteristics of the habitat?  

As we know now, the influence of factors like soil, and the presence of terrestrial materials like seed pods, leaves, and branches play a huge role in the chemical composition and appearance-of the water. It's really no different in the aquarium, right? Tannins from wood and botanical materials will leach into the water, providing the characteristic "tint" that we've become so accustomed to in our little niche.

Studying the characteristics of the igapo and varzea forests of Amazonia is just a start...these are the "textbook" examples of geologic influence on the aquatic environment- something that we can really run with in our biotopic interpretations of this habitat.

Yes, I also have this irresistible curiosity about the potential of botanical-influenced substrates to foster denitrification. With the diverse assemblage of microorganisms and a continuous food source of decomposing botanicals "in house", I can't help but think that such "living substrates" create a surprisingly diverse and utilitarian biological support system for our aquariums.

I think that the idea of an "enriched substrate" will become an integral part of the overall ecosystems that we create. Considering the substrate as both an aesthetic AND functional component- even in "non-planted" aquariums, opens up a whole new area of aquarium "exploration."

And its impact on water is already an obsession to many of us, right?

I envision that the future of mainstream aquarium practice may include creating such a substrate as simply part of "what we do." Adding a mix of botanical materials, live bacterial and small organism cultures, and even some "detritus" from healthy aquatic systems may become how we establish systems.

It's not some amazing "revolution"- it's simply an evolution of practices that we've been playing with peripherally for decades in the hobby.

It's all about what happens when water, soil, weather, and fishes interact.

Stay excited. Stay fascinated. Stay studious. Stay brave. Stay creative. Stay diligent...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

May 24, 2020


The fishes know it...

As hobbyists, we spend enormous amounts of time, money, and energy attempting to create the ideal aquascape for our fishes. And, let's face it; pretty much no matter how we 'scape a tank- no matter how much- or how little- thought and effort we put into it, our fishes will ultimately adapt to it.

They'll find the places they are comfortable hiding in. The places they like to forage, sleep and spawn. It doesn't matter if your 'scape consists of carefully selected roots, seed pods, rocks, plants, and driftwood, or simply a couple of clay flower pots and a few pieces of egg crate- your fishes will "make it work."

It's what fishes do. It's what they've done for eons.

And as aquarists, what we've collectively and admirably done for a century or so is try to create optimum conditions for the fishes we keep. This includes both the physical-structural and chemical environment. We've talked a lot about the chemical environment, vis a vs our botanical-style/blackwater aquariums. Today, let's just think for a few moments about the physical-structural environment we create for our fishes, and why.

When we're planning an aquascape, we spend an enormous amount of time selecting the right materials- rocks, wood, botanicals, etc., to get the right "feel" to our 'scape. This is a most enjoyable and interesting phase of an aquarium build, for sure- but take yourself out of the "I'm-gonna-enter-THIS-ONE-in-the-aquascaping-contest-and-place high" mindset for just a second, and put yourself into the mindset of...a fish.

Yup. Think like a fish for a second. 

I mean, sure, I'll bet that fishes like living in those insanely cool 'scapes you see in all of the contests; however, those are mainly designed and constructed for the pleasure of humans, right? They're designed for our tastes. Specifically, for human judges, who evaluate a design-based on a set of specific criteria. "Iwagumi" looks really cool, but I'd hazard a guess that you won't find many of these "submerged Stonhenge" features in the natural streams and rivers of the world.

I'm just gonna go out on a limb and make that speculation...

So what about considering just how the fishes interact with the aquascape you create? 

My suggestion?

Again: Think like a fish a bit more.

Really. It might be kind of fun-and educational- to think about where your fishes are found in the natural streams, lakes, and rivers they come from...and "work backwards." I mean, fisherman have been doing this for eons...why not fish hobbyists?

It makes perfect sense, because, well, we have a pretty fair collective understanding of how fishes interact with their environment, don't we? 

I think so.

Let's look at some of the features in natural bodies of water where fishes are commonly found...this might give you some insight into how to incorporate them into an aquascape. 

I need not discuss flooded forests all that much, because we've pretty much written more on this topic than just about anything over the years...Suffice it to say, my obsession with these unique habitats is well-founded; they are filled with amazing features, ranging from tree trunks to root tangles, to submerged terrestrial plants and leaf litter- all of which we can replicate in the aquarium in dramatic fashion.

And then there are flooded Pantanal meadows- essentially grasslands with low scrub brush and plants, which are flooded seasonally, providing a rich and diverse underwater habitat for a variety of fishes. These habitats, equally as engrossing as the flooded forests, are seldom replicated in the aquarium, fore reasons that I cannot quite understand. Perhaps it's the "dirty" aesthetic which has thrown us off? Regardless, the fishes make use of the submerged grasses and vegetation for foraging and spawning among.

And of course, there are many features of streams and rivers that fishes LOVE to congregate in...Think about how you might consciously incorporate some of them into your next aquascape!

First off, a few "sweeping generalities."

Fishes tend to live in areas where the food and protection is, as we've talked about previously. Places that provide protection from stronger current, and above-and below-water predators. Places where they can create territories, interact, spawn and defend themselves.

Bends in streams and rivers are particularly interesting places, because the swifter water movement will typically carry food, and the fishes seem to know this. And if theres a tree branch, trunk, or a big rock (or rocks) to break up the flow, there will be a larger congregation of fishes present.

So, the conclusion here is that, at least in theory, if you design your 'scape to have a higher "open water" flow rate, and include some features like rocks and large branches, you'll likely see the fishes hanging in those areas...

In situations where you're replicating a faster-flowing stream environment, think about creating some little "rock pockets", perhaps on one side of the aquarium, to create areas of calmer water movement. Your fishes will typically orient themselves facing "upstream" to catch any food articles that happen on by. So, from a design perspective, if you want to create a cool rock feature that your fishes will likely gather in, orienting the flow towards it would be a good way to accomplish this in the aquarium. 


Among the richest habitats for fishes in streams and rivers are so-called "drop-offs", in which the bottom contour takes a significant plunge and increase in depth. These are often caused by current over time, or even the accumulation of rocks, leaves, and fallen trees, which "dam up" the stream a bit. (extra- you see this in Rift Lakes in Africa, too...right? Yeah.) 

Fishes are often found in drop offs in significant numbers, because these spots afford depth (which thwarts the hunting efforts those pesky birds), typically slower water movement, numerous "nooks and crannies" in which to forage, hide, or spawn, and a more restive "dining area" for fishes having to contend with strong currents. From an aquascaping perspective, this gives you a lot of cool opportunities.

If you're saddled with one of those seemingly ridiculously deep tanks, a drop-off could be a perfect subject to replicate. And there are even commercially-made "drop-off" tanks now! With a little observation of natural habitats, some planning, and a bit of creativity, there's no limit to how effective a recreation of this habitat you could accomplish!

Overhanging trees are common in jungle areas, as we've discussed many times. Fishes will tend to congregate under trees for the dimmer lighting, "thermal protection", and food (insects and fruits/seeds) that fall off the trees into the water. And of course, if you're talking about a "leaf litter" or botanically-influenced aquascape, a rather dimly-lit, shallow tank could work out well.

Lots of leaves, pieces of wood in a "tree-root" like configuration, and some seed pods would complete a cool look. For a cool overall scene, you could introduce some riparian plants to simulate the bank as well. A rich habitat with a LOT of opportunities for the creative 'scaper!

Why not create an analogous stream/river feature that is known as an "undercut?" Pretty much the perfect hiding spot for fishes in a stream or river, and undercuts occur where the currents have cut a little cave-like hole in the rock or substrate material near the shore.

Not only does this feature provide protection from birds and other above-water predators, it gives fishes "express access" to deeper water for feeding and escaping in-water predators!

Trees growing nearby add to the attractiveness of an undercut for a fish (for reasons we just talked about), so subdued lighting would be cool here. You can build up a significant undercut with lots of substrate, rocks, and some wood. Sure, you'd have some reduced water capacity, but the effect could be really cool.

Leaves, the "jumping off point" of our botanical obsession, form a very important part of these stream habitats. They fall from the trees, accumulate in the water, and work their biological magic.

It is known by science that the leaf litter and the community of aquatic animals that it hosts is, according to one study, "... of great importance in assimilating energy from forest primary production into the blackwater aquatic system." 

It also functions as a means to preserve the nutrients that would be lost to the forests which would inevitably occur if all the material which fell into the streams was simply washed downstream. The fishes, crustaceans, and insects that live in the leaf litter and feed on the fungi, detritus, and decomposing leaves themselves are very important to the overall habitat.

In the aquarium, leaf litter and botanicals certainly perform a similar role in helping to sequester these materials.

As we've talked about before briefly, another interesting thing about leaf litter beds is that they actually have "structure" and even longevity. In several studies I read on the subject, the accumulations of leaves in various streams are documented to have existed in the same locations for years- to the point where scientists actually have studied the same ones for extended periods of time.

Some litter beds form in what stream ecologists call "meanders", which are stream structures that form when moving water in a stream erodes the outer banks and widens its "valley", and the inner part of the river has less energy and deposits silt- or in our instance, leaves.

There is a whole, fascinating science to river and stream structure, and with so many implications for understanding how these structures and mechanisms affect fish population, occurrence, behavior, and ecology, it's well worth studying for aquarium interpretation!  Did you get that part where I mentioned that the lower-energy parts of the water courses tend to accumulate leaves and sediments and stuff?

There are other interesting structures in streams which we would be well served to study and replicate in our aquariums. Streams typically feature two interesting biotopes that we haven't really discussed in much detail here, and both of which are quite profoundly impacted by the seasonal rains:

Pools, with slower current and a substrate covered mainly by deposits of leaf litter, detritus and driftwood; and "riffles" (defined as shallow sections of a stream with rapid current and a surface broken by gravel, rubble or boulders), with a moderately-fast-flowing current and mostly sandy bottom with tree roots, driftwood pieces, and small rocks and pebbles. (ohh...home to Darter Characins!


These "riffles" are considerably more significant in the wet season, when the obvious impact of higher water volumes are present. In the Amazon, for example, you'll find an unexpected abundance of some species familiar to us as hobbyists in these "riffles." Species like Pyrrhulina brevis, Hyphessobrycon melazonatus, and Hemigrammus of various forms, and even some Nanostomus, and the killie Rivulus compressus.


Interesting "factoid": Some scientists have postulated that the higher presence of nocturnal predators in the pools adjacent to the more active riffles might increase the number of species that seek refuge in the riffles to avoid them! And Rivulus, which usually live in more intermittent pools along the stream edges, outside the main stream channels, are normally found at night in these riffles!  

Reduction of stress. Indeed, survival. That's pretty important in the I'd imagine it's equally as important in the aquarium.

In the end, design and build the aquascape that makes you happy.

However, if you're trying to create something a bit different and perhaps a bit more true to nature, you might want to take a little "field trip" to a nearby stream, river, creek, lake, etc., where fishes and other aquatic animals reside, and observe things from the perspective of how they interact with the features of the environment. 

You should "get outside" and do this once in a while! You'll definitely leave with some inspiration, ideas, and just maybe, a slightly different perspective on aquascaping than you've previously had! 

Gaining a fresh perspective and new inspiration for your hobby is never a bad thing! So, "thinking like a fish" isn't such a bad idea, is it?

Yeah, the fishes know it. You should, too.

Stay fascinated. Stay inspired. Stay creative. Stay curious. Stay unique....

And Stay Wet.


Scott Fellman

Tannin Aquatics 

May 23, 2020


Here's mud in your...tank? Question everything.

One of the things I like about the approach that we are taking to natural-style aquariums is a willingness to look at things a bit differently; to occasionally push the boundaries back on what is considered "normal" practice and the "tried and true." We've talked so often about the need to make "mental shifts" and turn towards Nature, rather than the traditional hobby practices, for a variety of things that we do. I think that this opens up more possibilities than ever before for those who are willing to do the work and venture out on the roads less travelled.

As you know, we talk a lot about substrates here- particularly in the context of their environmental impact on our aquariums. Not simply as an aesthetic enhancement to an aquarium, but as a crucial environmental enhancement component. The idea of re-imagining the materials, practices, and the ways we incorporate various materials into the substrates of our aquariums is prime for disruption (Okay, I had to use that expression!). Sure, at first glance, you might think to yourself, "Who cares? What's so incredible about substrates and why do we need to change anything?" 

Fair enough. For many years, they haven't really been considered much more than the metaphorical "window dressing" for our tanks. We've seen some evolution of them for aesthetics and for plants, but that's been about it. 

However, the reality is that aquarium substrates can have such an impact on our little ecosystems, beyond just creating a "look." Not surprisingly, we've seen a lot of developments in the area of planted aquarium substrates- creating nutritional media for aquatic plants to grow in and thrive. This has been a big thing for the hobby, of course. However, with few exceptions (I've seen "shrimp-centric" substrates) it's been focused solely the needs of plants- not the aquatic environment as a whole.

I think it's time to change that in a big way.

And it starts with re-thinking what we use. If we want to replicate the wild aquatic habitats of the world, we need to consider what they actually are.

It starts with finer, siltier, more "soil-like" substrates- Now, sure, there are many habitats which are comprised of fine sands, and even coarse gravels, as we've incorporated into our aquariums for a century now. However, many, many natural aquatic systems have substrates comprised of clay, minerals, silt, and soils- perhaps with a smattering of fine quartz or other sand. I'd go out on a limb to suggest that many, if not most- of the intriguing habitats we are interested in replicating in our natural aquariums have substrates unlike anything we typically utilize in the hobby.

For some time, I've been very intrigued about the terrestrial and other soils that hobbyists who keep "dirted" planted aquariums have utilized for years to facilitate amazing plant growth. However, I'm not talking about them for growing plants- I'm talking about using these materials for the primary substrate in the natural, botanical-focused aquarium, in which plants may or may not play a role. Now, sure, there are considerations- such as an influx of a lot of nutrient-laden materials into the aquarium (not as important if you're growing plants, of course), and the sheer "messiness" of soils, clays and silt-which have created some consternation among those who use them. Sure, these materials are easily disturbed and can create some rather turbid conditions in the tank as they settle. 

I've heard about concerns over gasses and such being trapped under the soil substrate (likely more of a concern when you're employing a "cap" of sand or other material on top of the soil/silt/clay to retain it) and being released into the tank during maintenance and other activities. Now, in my experiments, I have not experienced this. I don't use a "sand cap" on top of my "dirt"- rather, I tend to mix in bits of crushed leaves, botanicals, and twigs, which seems to not only keep the materials together, but enhances the natural, "random" look. I gradually saturate and "flood" these tanks, a sort of analog to what happens in Nature during the periods of inundation in the forests.

I'm sure that I'll get a dozen emails from hobbyists telling me that it's irresponsible snd dangerous to utilize such an approach to substrate in a fish-focused tank, but in almost 7 years of personal experimentation with these types of mixes, I've never had any issues whatsoever- other than the aforementioned cloudiness when the substrate is disturbed. In fact, after a few months, even when the substrate is disturbed in one of these tanks, the cloudiness tends to not occur. Based on my personal experience, I believe that the longer this stuff is down, the more likely it is to STAY down.

Now, does this mean everyone should ditch the time-proven commercial substrate materials and jump head long into creating dirt and silt substrates in their display aquairums?

Of course not.

However, I think it's worth experimenting with.

It's very important to look at our long-held opinions about what aquarium substrates "should" be, and what their role is in the aquarium. We've long offered a variety of materials which we've rather generically called "substrate additives"- stuff you can mix in with conventional sand, soils or use as a primary substrate in experimental systems. Many of you have used our coconut-based coir substrate material, "Fundo Tropical"  or the finer "Substrate Fino" for this purpose over the years as an alternative to peat and such, and it remains a best-seller for I think you're finding interesting uses for this stuff, too.

I think that we should look at substrates in our aquariums as more than just "the bottom" or "a place to put rocks and wood and plants"- but rather, as a dynamic, living, integral component of a balanced closed ecosystem. A place to culture supplemental food organisms, facilitate reproduction of fishes (I'm thinking soil-spawning killies here), and impact the chemical composition of our water. It would be great to apply as much emphasis to substrate in this vein as we do to other components of the aquarium. It's about mental shifts; re-thinking the "how's" and "why's" of what we've done for so long.

A "substrate" can be- should be- way more than gravel or plain old sand.

And if we have our say in the matter, it will be!

If one studies the composition of the substrates in the flooded forest habitats of South America that we obsess over, they are mainly comprised of clays, soil, and silt, with a whitish quartz sand in some more permanently inundated areas. The igapo tend to have a less diverse and species-rich plant/tree population because the soil which comprises this habitat, known as podzol- tends to be more depleted of nutrients than the more dense, productive varzea habitat, which has a far "richer" soil.

Taking the time to study these habitats in their "terrestrial" state and understanding the composition of the soil and plant species which reside in them can make a huge contribution to our knowledge as we attempt to replicate them in our aquariums. Yeah, if you would have told me twenty years ago that I'd be reading scientific papers about, well- dirt- on the forest floors of Amazonia, I would have been like, "Um, yeah...right..."

However, the reality is that in order to replicate these rich flooded forests as an aquatic habitat, we need to understand them in their terrestrial state as well. Our friends who keep frogs and other herbs have an interesting understanding of these habitats, and we would do ourselves some good reaching out and discussing this sort of stuff with them!

One of the characteristics of our beloved igapo and varzea environments (flooded forest floors in South America), and indeed, many of the other tropical stream habitats worldwide, is a large number of roots in the substrate. The igapo, in particular, has a large number of smaller roots, because of the relatively nutrient-poor soils. To simulate this in the aquarium, you could utilize a variety of dried roots, or even small pieces of wood, like "Spider Wood", "Tangle Branch Wood", or even our "Nano" Asian driftwood, Mangrove Branches, etc.

In Nature, these roots don't just serve to provide nutrients for plants- they also create a protection against erosion and loss of sediments. In our aquariums, we can utilize the aforementioned materials to hold some of these materials together. And, sure, if you're really cutting edge, you can experiment with water-resistant terrestrial plants, like sedges, grasses, etc., which lay down significant root systems in these substrates.

"Functional aesthetics", again.

Now, what about maintenance? What are the issues? Well, much like any aquarium with substrate, you need to be smart, observant, consistent, and in the case of soils and such- patience- as these systems establish. You will need to feed and stock carefully, and sure, unless you like haziness, you'd be well served not to excessively disturb the substrate too much, particularly during the earlier phases of the tanks existence.

There is so much more to research, experiment with, and discuss in this area. We'll have a lot more to say about this stuff in coming months. We're excited about the possibilities which are arising as a result of this work. The potential to replicate- on many levels- the look, function, and dynamics of the substrates found in Nature.

The potential opportunities and breakthroughs are there...We just have to dig in and go after them!

That's where Tannin is headed. We're doubling down in coming months, beyond anything we've done before- and likely, with unique natural materials beyond anything available anywhere previously. There's no turning back now....

And of course, the long-awaited "Nature Base" substrates will be available soon...Get ready for turbid tanks, dark water, biofilms, and all sorts of coolness! 

Stay engaged. Stay resourceful. Stay observant. Stay patient. Stay intrigued...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



May 22, 2020


Yeah, you can use carbon!

Like so many things we work with in botanical-style aquariums, the idea of using chemical filtration media seems to simultaneously make sense, while also seeming kind of counter-productive! That's a bit confusing! 

I guess you have to think of it in the context of what we do, right?

Brown water and lots of leaves and botanicals seems like perfect recipe for either a really natural-looking aquarium, or a simple disaster...depending upon how you look at it!

As the practice of blackwater/botanical-style aquariums evolves and gains more and more traction, we seem to question some off our old habits, develop new ones, and dismiss some of 'em altogether. Techniques, ideas, and concepts start playing out and falling into place.

We receive a lot of questions about our opinion on using activated carbon in blackwater aquariums. Like, a LOT.

Now, for decades, carbon has been like THE premier form of chemical filtration for all sorts of aquarium application. As you might imagine, if used properly, carbon excels at removing dissolved organic compounds, certain "impurities", and...gasp- tannins- from the water. That seems kind of counter-productive...

Now, note the "used properly" part.

It's pretty well known that carbon is not a "set and forget" filter media. It's a chemical adsorbent media. That means that "stuff" adheres to it's surface. You use it to remove whatever it is that you're trying to remove, and then you replace it regularly..Like every two or three (if you're um, lazy...) weeks. Being an "adsorbent", stuff will adhere to it's surface, rendering it essentially useless very quickly as a chemical filtration some point, it's just accumulating biofilms and becoming a biological filtration media.

Personally, I love the stuff, and rarely, if ever have ran an aquarium without it.

My bias towards using carbon in my aquariums comes from years of keeping reef aquariums, and later, co-owning a commercial coral importation/propagation facility, which had thousands and thousand of corals in tens of thousands of gallons of water.

Corals produce copious amounts of slime, mucous, and metabolic waste, not to mention "allopathic compounds" (ie; chemical "weaponry" used to defend their turf against intruders), and carbon, along with admittedly more efficient means, such as ozone and protein skimming, formed a sort of defensive "triad" to keep the animals healthy and water quality high.

Oh, and we also employed water exchanges, of course.

And yeah, we used a "shit ton" of the stuff in our facility! 

For reefers, the benefits of carbon use are really pretty apparent:

It reduces discolorations in the water.

It may bind some organic toxins.

It can be a place for beneficial bacteria to use as a "culture media."

It may remove copper and other trace metals (which bind to organic matter which, in turn binds to activated carbon for removal.

What about for us- the Blackwater/Botanical-Style aquarium crowd?

As we've discussed many times here, there is a sort of obsession those in our world have about keeping the water in our tanks dark and earthy-looking, and the idea of using chemical media with known adsorbent capability like carbon seems a bit "counter intuitive" to some. Carbon does excel at removal of compounds like phenols and tannins.

I'll often tell people that I use it more-or-less "full time" in my blackwater, botanical style displays, and this elicits the online equivalent of raised eyebrows now and again. "Tinters" will ask, incredulously, "Doesn't this stuff remove the color from the water?" To which I respond, "Yes, it some extent."

Please do look at some pics of my tanks, and tell me if I've been removing "too much" tint via my use of carbon!

The key to keeping your tank "tinted", as we've mentioned before, regardless of wether or not you use carbon is to continuously replenish the materials you use to tint your water (leaves, etc.). Think about botanicals as "consumables", in that they need to be replaced on a regular basis to maintain the characteristics you want in your aquarium.

So, now one could probably make some sort of argument that using the carbon the way I do is actually sort of inefficient...Especially if I'm replenishing the botanicals as fast as the carbon removes the effects they impart, then changing out the carbon. Yeah, I'm keeping the manufacturers happy, I suppose!  

However, my real "secret" is to use less than the manufacturer's recommended dose. I use about half of what is typically recommended. Thus, I will still get some of the benefits (ie; removal of excess organics), while still keeping that tint which I love so much.

I suppose one could question my approach.

I mean, is the stuff really even doing anything when employed this way? Just sort of playing "tug-of-war" with the tannins? I say sheepishly, "Likely."  Carbon performs a number of functions when it comes to water purification. Not all of them are immediately apparent. Yet, the benefits of carbon use are manifold. For example, carbon is perfect for a "prefilter" in reverse osmosis units, removing impurities to protect the delicate membranes that do the magic.

That's like the ultimate "best" aquatic use for carbon, if you ask me. (And don't get me started about RO/DI until. Suffice it to say, if you're into this kind of aquarium, you should invest in one. Period. Full stop.)

Yes, carbon excels at a number of things.

However, it also removes various dissolved organic compounds, which tend to enter our aquariums when we toss in- ohh- I don't know- leaves, seed pods, wood, etc.  Stuff like that. An excess of these organics could have some long-term impact on water quality, leading to algal growth and/or accumulation of nitrate over time. So carbon sort of acts like a very "first line of defense" against the accumulation of these compounds.

And yeah, we'll hear the occasional story of the hobbyist who dumped his/her entire "Enigma Pack" into an established 20-gallon tank at one time, despite our instructions not to, creating- well, "issues" with water quality. While not being able to remove everything you throw at it, carbon "in situ" could at least be helpful in removing excesses in emergency situations like that until you can execute a water exchange.

Of course, it's not a "cure-all", but carbon can help in these types of scenarios.  

It should be noted that activated carbon does not remove all possible toxins or unwanted chemicals, including the ammonia produced by animals, and nor does it substantially affect carbonate hardness of the water. Other compounds that activated carbon has little or no ability to remove include stuff like calcium, carbon dioxide, fluoride,  magnesium, nitrate, nitrite, phosphates, sodium, and iron.

Of course, it's important to use carbon correctly. Carbon should be placed after the mechanical filtration media in the filter, where water will flow through it with little restriction. Otherwise, the stuff will clog with debris and other solids, significantly reducing its available surface area for chemical adsorption. Make sense? Oh, and in these scenarios, activated carbon does recruit biofilms and their constituent bacteria, becoming a sort of biological filter. So, although this could be seen as a sort of collateral benefit, if you let your carbon sit too long, in a strange twist of irony, the sudden removal of portions of the natural biological filtration could actually be counter-productive-cause a sudden decrease in water quality!


I employ a relatively small amount of the stuff (like about 4 ounces/114 grams) in an area of my filter where significant water flows through it. When I use carbon, I change out the stuff every two weeks without fail. One other "argument" against carbon is that it will remove medications from the water. Well, yeah it does- and that's important in a "hospital tank", dedicated solely to treating your fishes. However, if you're medicating your display tank, particularly with the intent of being "prophylactic" I personally feel that it opens up other important why you're not doing this in a quarantine tank and medicating the display tank instead?

That being said, carbon- like any filtration media, or piece of equipment, should never be used as a replacement for common sense husbandry- specifically, regular weekly water exchanges. In fact, personally, I'd rather more people ditch the use of carbon and simply rely on water exchanges to remove dissolved organics and other undesirable compounds, from their aquarium water, especially if it encourages more diligent husbandry over just developing a "dependency" on a product.

All that being said, carbon and other chemical filtration media have their place, when used responsibly and as part of a comprehensive regimen of aquarium husbandry.

Alternatively, I use other chemical media, such as "Poly Filter", which is really my "go to" for pretty much every aquarium I keep. I also love the carbon "alternative", Seachem "Renew", which works very well. Yet another promising filter media is SeaChem's "Hyper Sorb", a synthetic synthetic adsorbent which, according to SeaChem's own "FAQ's" indicates that it's their "go-to" for use in blackwater aquariums! I love everything they make, so if the experts at SeaChem are giving Hyoer Sorb their blessing for blackwater, who am I to doubt it?

Again, a lot of my personal practices are based on habits formed over a lifetime of personal and professional aquarium keeping, and some of them, quite frankly, are not the best way to go for everyone.

Some might even be a bit...well, inefficient.

Old habits sort of die hard with me, I admit!

However, the idea of creating some sort of emergency "safety net" for water issues is appealing to me, having seen a lot of "situations" over the years. Utilizing carbon or other media works for me.

It just makes me feel better.  Yeah, that's hardly a scientifically-supported, perfectly "technical" reason to do something in the aquarium hobby, but hey, no one ever accused me of being 100% logical, so...

Perhaps it's simply a quirk of mine!

So, what's the answer to the question: To use, or NOT to use carbon in YOUR blackwater/botanical-style aquarium? 

Well, if it's used correctly, replaced frequently, and you understand what it can and cannot do, I see it as a sort of "insurance policy" for your aquarium. On the other hand, a well-managed aquarium in which common-sense husbandry is practiced (careful stocking, feeding, frequent water exchanges, etc.) doesn't really "need" it, IMHO, yet you should simply have some on hand for emergencies.

Sure, this is a question with supporters on both sides of the fence, and both positions are perfectly justifiable. At the end of the day, IMHO, using carbon is just another one of those things every hobbyist should at least have a basic understanding of, and keep in his/her aquarium "toolkit."

I've always felt it better to have than "have not."

But I am a bit weird, as you already know.

Stay observant. Stay curious. Stay prepared. Stay proactive. Stay curious. Stay diligent. Stay informed...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



May 20, 2020


How to succeed at a botanical-style aquarium without really trying...

Okay, that's probably one of the worst blog post titles I've come up with lately, but it might make some sense.

The idea of creating an aquarium filled with leaves, seed pods, and other botanicals is as much a leap of faith as it is a practice. We're talking about adding all of this stuff to your tank and then letting Nature "do her thing" to a certain extent. As we've (painstakingly) analyzed over the years, adding these materials to an aquarium not only impacts the aquatic environment- it actually creates it- biologically, chemically, and physically. 

So, how difficult is the idea of creating and managing a botanical-style aquarium, really?

I mean, it's not THAT hard. The hard part is deploying patience, and the need to observe and go slowly when setting up your tank; allowing natural processes to occur and play out. And you need to learn a little bit about basic water chemistry...stuff you likely should already have a grasp of, right?

As we've discussed many times here, if you're starting with a brand new aquarium, you can stock the shit out of it with botanicals and leaves and such. Since you have no existing fishes I the tank, you'd simply add your selections of botanicals and cycle the tank in your fave manner. Add fishes when ammonia and nitrite levels  have stabilized. This is not all that different from establishing a reef aquarium. Before you add the fishes, you need to create a stable aquatic environment.  You need to test. You need to deploy patience and common sense. 

And you need to educate yourself.

And you need to have a game plan. It's not just, "Let's throw all sorts of stuff into the tank and we have an instant blackwater aquarium!" Nope. You need to have some sort of game plan that dictates not only the type of materials that you add- but in what quantities and with what intentions. Are you trying to create a certain "look?" Are you trying to create optimum environmental conditions to breed a certain fish? Are you wanting to impact the pH of the tank? Have really darkly tinted water?

One thing to note: Keep in mind that you need to utilize water with little to no carbonate hardness to have anything but the most negligible impact on pH in your tank. There has been this long held "aquarium urban myth", perpetuated by hobbyists who simply haven't had first hand experience, as well as certain vendors who are- well, let's call them what they are- morons- that adding Catappa leaves, Alder cones, or whatever will enable you to dramatically lower the pH of your tap-water-filled aquarium with little or no effort and create "Instant Orinoco" conditions.

These kinds of regurgitated bullshit hyperbole claims need to stop, as do the over-generalized (often incorrect) assumptions of what botanicals can and cannot do. They damage the hobby and the botanical-style aquarium movement by offering false hope and unrealistic expectations to the aspiring botanical-style aquarium enthusiast. We need to spend the time researching these things before we leap. We need to put in the work to learn about what to really expect before we can have an "Instagram-ready" tank to share! 

I know, it sounds like a bit of a buzzkill; I hate to be the "sugar in your gas tank", but it's important to be realistic and be informed. There are tons of resources, beyond just our blog, about how pH and hardness work. There are a lot of articles on water chemistry, the nitrogen cycle, reverse osmosis, and on wild blackwater habitats and how they function. You need to put in the work and research them. Personally, I receive several emails a week from hobbyists who purchased botanical materials from vendors around the world, who have some of the most basic questions and are disappointed because the stuff they purchased from "XYZ Botanicals" didn't lower their pH, or killed their fishes, or whatever.

CRAZY MICRO RANT TIME: To my fellow vendors- an appeal...A request. No, actually a challenge: STEP UP YOUR GAME! Don't just try to make a quick sale by luring in the uninformed and inexperienced, and promising them some sort of fantastic results...and then, in an act of unmitigated gall- refer them to our site or to ME for the "education." I've seen a few of you guys out on social bragging about your vast experience, passion, ability to source stuff, and such...Great- So, why don't you share it? Where is your blog? Where is your podcast? Why is it so easy to sell the stuff, but apparently even easier to take no responsibility to educate the customer? Why do you "sub-contract" it out to me? If you don't make this effort to help your suck. Period.

Don't suck.

Whew!! Rant over. For now.

Obviously, I'm happy to help. Our blogs, podcasts, videos, live events, etc are free for everyone to make use please do. And of course, you can hit me up with your questions. However, the answers to many of them are right here for the taking. Oh, and we're doing a book, too- so soon, it will be even more concise!

Anyways, back to the topic...

With regards to adding botanicals to an established, stable, populated it slowly. Monitor water parameters. Observe. Test. 

Simple. Logical. 

There are not concepts unique to our specialty...

Like so many things in aquarium keeping, the extent to which we put our animals lives at risk is in our hands. Using botanicals to help foster "blackwater" conditions in an aquarium is no more dangerous than any other aspect of fish care. It's not all doom and gloom...You simply need to be aware of the potential of these materials to impact the aquatic environment, just like anything you add- from substrate to rocks, to driftwood-in any type of aquarium. 

This is no different than running an African Rift Lake cichlid tank or a reef aquarium- you need to be aware of what's going on in your water...part of the game. Blackwater aquariums, like many other "specialty" aquaria, are not "set and forget" systems. They require monitoring, management, and observation on a continuous basis.

And preparation of the materials you add is crucial.

Like many of you, I've made my share of errors in this hobby. Almost all of them involved rushing stuff, taking shortcuts, or getting too "relaxed" in my practices. 

When I started playing with botanicals in my aquariums almost two decades ago, I made a fair number of mistakes. Sometimes, they cost the lives of my fishes. And killing fishes sucks.


Some mistakes were caused by my lack of familiarity with using various materials. Others were caused by not understanding fully the impact of adding botanical materials to a closed aquatic ecosystem. All were mitigated by taking the time to learn from them and honestly asses the good, the bad, and the practical aspects of using them in our aquariums. 

And sometimes, that meant developing "best practices" to help mitigate or eliminate issues as much as possible, even though the "practices" may not be the easiest, most convenient, or expedient way to proceed.

After more than four years of running Tannin, I have pretty much identified the two most common concerns for customers associated with utilizing botanicals in their aquariums. Curiously, our two biggest concerns revolve around our own human impatience and mindset- not the botanical materials themselves.

The first is... preparation.

We are often asked why we don't feel that you can, without exception, just give any of your botanicals "a quick rinse" and toss them into your aquarium.

After all, this is what happens in nature, right? Well, shit- yes...but remember, in most cases, there is a significant "dilution factor" caused by larger water volumes, currents, biologically-rich substrates, etc. that you encounter in natural aquatic systems. Even in smaller bodies of water, you have very "mature" nutrient export systems and biological equilibriums established over long periods of time which handle the influx and export of organic materials.  

However, even in Nature, things go awry, and you will occasionally see bodies of water "fouled" by large, sudden influxes of materials (often leaves, grass clippings, etc.)- sometimes after rain or other weather events- and the result is usually polluted water, large algal blooms, and a pretty nasty smell! 

In the aquarium,  of course, you have a closed system with a typically much smaller water volume, limited import of fresh water, limited filtration (export) capacity, and in many cases, a less robust ecological microcosm to handle a large influx of nutrients quickly.

So you know where I'm going with this:

Fresh botanical materials, even relatively "clean" ones, are often still "dirty", from collection, storage, etc. They may have dust, airborne pollutants, soil or silt (depending upon where they were collected), even cobwebs, bird droppings, and dead insects (yuck!).

Natural materials accumulate "stuff." They're not sterile; made in some clean room in a factory in Switzerland, right? 

So, "just giving botanicals a quick rinse" before tossing them in your tank is simply not good procedure, IMHO- even for stuff you collect from your own backyard. At the very least, a prolonged (30 to 60 minute) steep in boiling hot water will serve to "sterilize" them to a certain extent. Follow it with a rinse to remove any lingering dirt or other materials trapped in the surfaces of your botanicals.

Now, I don't recommend this process because I want to be a pain in the ass ( I mean, it's debatable that I am...). I recommend it because it's a responsible practice that, although seemingly "overkill" in some people's minds- increases the odds for a better outcome.

There is simply no advantage to rushing stuff.

Like all things we do in our aquariums, the preparation of materials that we add to them is a process, and Nature sets the pace. The fact that we may recommend 30 minutes or more of boiling is not of concern to Nature. It may take an hour or more to fully saturate your Sterculia Pods before they sink.

So be it.


Savor the process. Enjoy every aspect of the experience.  And don't you love the earthy scent that botanicals exude when you're preparing them.

How much to use?

Well, that's the million dollar question.

Who knows? Even that is a guess and decidedly unscientific at best! 

It all gets back to the (IMHO) absurd "recommendations" that have been proffered by vendors over the years recommending using "x" number of leaves, for example, per gallon/liter of water. There are simply far, far too many variables- ranging from starting water chem to pH to alkalinity, and dozens of others- which can affect the "equation" and make specific numbers unreliable at best. 

Now, nothing is perfect.

Nothing we can tell you is an absolute guarantee of perfect results...You're dealing with natural materials, and the results you'll see are governed by natural processes that we can only impact to a certain extent by preparation before use. But it's a logical, responsible process that you need to embrace for long-term success.

And when it comes time to adding your botanicals to your aquarium, the second "tier" of this process is to add them to your aquarium slowly. Like, don't add everything all at once, particularly to an established, stable aquarium. Think of botanicals as "bioload", which requires your bacterial/fungal/microcrustacean population to handle them.

Bacteria, in particular, are your first line of defense.

If you add a large quantity of any organic materials to an established system, you will simply overwhelm the existing beneficial bacterial population in the aquarium, which will likely result in a massive increase in ammonia, nitrite, and organic pollutants. At the very least, it will leave oxygen levels depleted, and fishes gasping at the surface as the bacteria population struggles to catch up to the large influx of materials.

This is not some sort of esoteric concept, right? I mean, we don't add 25 3-inch fishes at once to an established, stable 10-gallon aquarium and not expect some sort of negative consequence, right? So why would adding bunch of leaves, botanicals, wood, or other materials containing organics be any different?

It wouldn't.

So please, PLEASE add botanicals to your established aquarium gradually, while observing your fishes' reactions and testing the water parameters regularly during and after the process. Take measured steps.

There is no rush.

There shouldn't be.

It's interesting how the process of selecting, preparing and adding botanical materials to our aquariums has evolved over the time since we've been in business. Initially, it was all about trying to discover what materials weren't "toxic" in some way! Then, it was about figuring out ways to prepare them and make sure that they don't pollute the aquarium. Finally, it's been about taking the time to add them in a responsible, measured matter.

I think our biggest "struggle" in working with botanicals is a mental one that we have imposed upon ourselves over generations of aquarium keeping:  The need to control our own natural desire to get stuff moving quickly; to hit that "done"

And the reality, as we've talked about hundreds of times here and elsewhere, is that there really is no "finished", and that the botanical-style aquarium is about evolution. This type of system embraces continuous change and requires us to understand the ephemeral nature of botanicals when immersed in water.

I know I may be a bit "blunt" when it comes to these topics of preparation, practices, and patience- but they are critical concepts for us to wrap our heads around and really embrace in order to be successful with this stuff.

All caveats and warnings aside, the art and evolving "science" of utilizing natural botanical materials for the purpose of enriching and influencing the environment of the aquarium is an exciting one, promising benefits and breakthroughs that we may not have even thought about yet! It's okay to experiment.

SO in summary- there IS no way to create a successful botanical-style aquarium without really trying...but you probably guessed that already, huh? The successful botanical-style tank- ANY successful tank, for that matter- requires you to be patient, employ discipline, observation, and education.

That's the easy part- and the hard part- depending upon how you look at it, right?

So, before you jump, make that effort to educate yourself and get really smart about this stuff...And share what you experience on your journey- all of it- the good and the occasional bad. It helps grow the hobby, foster a viable movement, and helps your fellow hobbyists!

That's pretty cool, right?


Until next time...

Stay thoughtful. Stay educated. Stay observant. Stay patient...

And Stay Wet.


Scott Fellman

Tannin Aquatics 

May 19, 2020


Trashing the "scavenger" stereotype!

Perhaps you're just like tend to analyze everything in this hobby!

I freely admit that I can be easily annoyed at times. And it's kind of funny what kind of stuff discussed in our hobby can just set me off. It typically happens when I am scouring aquarium forums ( as is part of my daily ritual) and come across some sort of discussion that demonstrates the strange indifferences we tend to demonstrate towards aquatic animals at times.

I came a cross a few discussions in which new aquarists were asking the age-old questions, "What are the best fishes to eat algae and keep my tank clean?" and "What's a good 'cleanup crew' for my community tank?"

Innocent enough, right? I mean, not really a big deal, huh?


This is a question that, in my fiesty, ripe old age, makes me a little bit concerned, actually. In fact, it kind of gets me pissed off a bit. Yeah. I mean, there should be a lot of other things about this hobby that get under my skin, but this one sort of does it for some reason. I mean, here we are in the 21st century, with every technological advantage possible- devices, techniques, and methodologies designed to maintain pristine water quality and beautiful aquariums, and we're still sort of "deferring" the maintenance duties to fishes and other animals...? 

(Peckolitia compta L134- Just an "algae eater?" I should think not!)

Makes you think a bit. 

I think we lean a bit too much on various animals to perform some of the "roles" that we need to have a better grasp of...This is in stark contrast to setting up an aquarium which accommodates the specific needs of certain fishes or animals. 

We'll get back to that later on.

The irony is that we have given these animals “duties” in our aquariums  when, in reality, they are simply behaving as they have in the wild for eons. We’re assigning a “role” to their existence based on our needs…Weird, huh? Or kind of "arrogantly presumptive", maybe?

Okay, I can see there will be a few who will say, "Fellman, you're being sort of hypocritical in your arguments here..." Well, perhaps, but I'd love to see us look at this from a slightly different perspective... (as we're known to do now and again!)

There are a lot of animals which are selected by us hobbyists for this "role" in aquariums  Many are of debatable value in terms of consuming things that we don’t want in our tanks. Others are without debate perfectly suited for what we want them to do. Some arrive in our tanks from plants or driftwood from other aquariums as sort of "hitchhikers", in a decidedly natural manner, without our intervention.

Others are deliberately added to our aquariums as part of what we think are necessary "cleanup crews." The composition of these “cleanup crews” is a well-discussed topic…We’ve dutifully assembled rosters of animals that we feel will do the job at removing the stuff we don’t want in our tanks, like algae, uneaten food, and "detritus." (don't start me on that shit, please.)

(An "Algae Eater!" Don't get me started with this one....)

Everyone has their opinions of what animals are best, and how many you should have. “X” number of this-or-that per gallon/liter, or some such nonsense. I think it’s absurd. I mean, really, who has done studies on how much algae an individual snail will consume in nature? Yet, we as vendors and hobbyists come up with exotic formulae…based on…what, exactly? And how much algae can support “X” number of snails in an aquarium, and for how long? At some point, food supplies will be exhausted with a large population of these animals in residence.

Then what?

I mean, if I were a snail, I wouldn’t want to share my 30-gallon tank with 15 other hungry neighbors. I’d just want the space for myself, or maybe a few friends of the opposite sex. More food, more fun…If you can call a snail’s life “fun”, that is.

Now, yeah, it is a bit more of an "art" than a "science"- and no one really has the perfect answer. And sure, I sell fish stuff for a living, so who am I to make such assertions and proffer my criticisms? Well, I'm just another hobbyist asking questions. We've discussed this before, but it comes up a lot in discussions.

This is a pretty common thing in the reef aquarium world, where you see vendors selling packages of snail, crabs, shrimp, and starfishes as "cleanup crews." At first it seems innocent, but beneath the shiny veneer, it's actually kind of dark and sad: We consider these animals a sort of "disposable" and "temporary" commodity- using them for their "cleaning services" until we have no more algae or detritus or uneaten food or whatever in our tanks. Then, if they live, great. IF they perish- well, we can always get more, right?


The "commoditization" of life forms for our tank maintenance...great...

Yep, I see this in the reef aquarium world all the time:  Recommendations for large number of animals like Brittle Stars and such to handle "detritus"...One of the big problems I have with some of the more “traditional” detritivorous “cleanup crew” members is that they are often animals that consume detritus as a part of their diet, and make a greater part of their diet the micro and/or macrofauna that you are so carefully trying to cultivate for your biodiveristy and nutrient export processes.


To make matters worse, hobbyists are often advised to keep stupidly large numbers of these animals in their reef aquariums, which assures that not only will they decimate your beneficial infauna, but they’ll probably slowly starve to death as a result of their own "efficiency." I mean, Brittle stars and some of the snails we use are good at getting at detritus, but if part of what they are consuming are animals that you want in your system, particularly in your sandbed- then its a considerable tradeoff, isn’t it?

It's no different in freshwater, really. The "cast of characters" is slightly different, but that's it. The "mission" we've assigned these animals is the same: It's all about eliminating algae and "detritus" in what we consider a "natural" way.

Let’s talk about the apparent dreaded "enemy" of clean tanks…detritus!

Detritus (or “detrus”, as one of my local reefer friends annoyingly refers to it with his typical malapropisms) is a great scientific-sounding “catch all” term for “stuff” that accumulates in your rock and sand- mainly, partially decomposed or uneaten food,  mucous, fish waste, etc. The working definition is “non-living” organic material; or more properly, organic-rich particulate material. Although continuously broken down by microorganisms in a healthy, established aquarium, some of the materials are not completely consumed by these lower organisms, and can be at least initially “worked over” by detritivorous animals and fishes.

Is it bad? Well, yes and no.

I mean, if the materials in the detritus continue to break down, they can create less hygienic conditions in a closed system, or provide “fuel” for nuisance algae growth. However, if you embrace it and view it as a supplemental food source for your animals, which it is- it doesn’t seem all that bad, huh? When we've talked about deep leaf litter beds as a possible means for cultivating supplemental food for our fishes, and have experimented with "inoculating" these beds with animal like worms and such, it's not so scary!

Fungal and bacterial growths act on it, and also serve as supplemental food sources for many fishes in our aquariums...Perhaps detritus is "fuel" for kickstarting our closed ecosystems? Food!

Okay...that's it for now for detritus.

I mean, based on numerous field studies I've read, that it's a pretty safe bet that many fishes of all types will consume this stuff as part of their diet. Assigning a fish to the exclusive role of "detritus cleaner" is a bit, well...arrogant on our part. Like, they're supposed to ignore all of the good stuff you feed the other fishes and simply subsist on detritus alone?  This is, I suppose, where I admit that my argument gets a bit weaker...

But what about algae..and those snails we "employ" to take it out. We like to add snails, right? At least they're cool for a while, until they multiply. And lot of these snails will reproduce along the way, sometimes creating large populations. So what do we do? We purchase "Assassin Snails" to take 'em out.

So...We're using another animal in a limited role to solve a "problem" that we sort of created in the first place by using a different animal for a limited role...


(The "Assassin", Clea helena. Pic by Snek01, used under CC BY-SA 3.0)

So when I see people asking about fishes as designated "algae eaters", I tend to get that familiar uncomfortable feeling. Yeah, a lot of fishes love eating algae, but I think we need to look at them for what they are: Cool little fishes (Otocinculus cats come to mind) that are interesting and enjoyable in their own right, which happen to consume algae as part of their diet. Not animals that we should stock in our tanks strictly for the purpose of taking it all out.

Fortunately, many of us have sort of "grown out" of this "stereotyping" thing for some fishes...I mean, when was the last time a serious hobbyist purchased a Plecostomus strictly as an "algae eater for their community aquarium?" Or a Corydoras as a "scavenger?"  On the other hand, it's not totally uncommon to see this thinking perpetuated in the general hobby arena...


(Corydoras sp. "CW008"- The perfect "scavenger?" I should think not! )

Try running that idea by one of the many hardcore Loricariid fanciers out there, who collect, keep, and breed these amazing fishes regularly! I don't think it will go over all that well...Your time would be better spent learning how closed aquatic ecosystems work, and how algae appear in significant amounts based on a set of characteristics which arise to facilitate their growth.

So, really, relegating these fascinating fishes to "scavengers" who are in our tanks for the sole purpose of keeping our tanks clean is a little "out there", really In fact, it's unthinkable to lots of dedicated hobbyists! People set up entire fish rooms to keep these fishes in optimum environments. Entire collections are comprised of many beautiful plecos and corys.

However, I suppose it's understandable that we make up a "role" for them.  It's kind of our own fault.


We feel good about using "natural controls" for problems, and I think it's great...but we also tend to look at the fact that it's really OUR responsibility to keep the tank clean, right? We can enlist the help of animals who are known to consume algae and uneaten food...but I personally don't think we should make the only reason for any fish's inclusion in our aquarium one of a "cleanup crew" member. 

Back to snails again.. (this is like a tennis match, huh?)

If you do incorporate snails into your aquariums for this purpose-and I think you should...I say, start really small, adding just a scant few of these animals into your system at a time. Just because “experts” or vendors recommend “X” number per gallon doesn’t mean that’s an appropriate stocking level. Remember, these animals need to eat, and if they exhaust their food supply, they will perish. They'll multiply if they are happy, and if the food resources are why not start off with just a few?

Really. I mean, if the thought of introducing new algae-covered rocks and wood into your tank just to feed your large population of snails after they've exhausted the available food supply doesn’t appeal to you, then stock with just a few to start and see how they do.

Or just get really good at taking the stuff out yourself.

OR...learn to appreciate this stuff.

Yeah. Better.

You can always embrace biofilms, algae, and fungal growths for what they are: Nature's most efficient processors of biological material. Not quite as easy or sexy as buying a dozen Otos or 20 snails, but perhaps far better suited for the "role." (okay, I can see some smartassreader railing on me as a hypocrite for postulating that we "assign" nutrient export duties to fungi and bacteria...)

Let's make the effort to continue to teach new hobbyists the value of proper husbandry; the basic skills required to identify problems, concerns, and ongoing maintenance requirements in our aquariums. Understanding how attempting to re-create more natural-functioning environments and their ability to utilize nutrients and food inputs is a fascinating endeavor, and I think our botanical-style aquariums are a good place to start!

Water changes, algae scraping, feeding carefully, etc., all are more important than ever...We can't solely rely on a piece of equipment or an animal to do our jobs for us...

So sure- it's okay to incorporate these animals into your stocking plan, but be reasonable and humane in your assumptions. Treat them like the treasured living creatures that they are. 

Play an active role in the process of maintaining your tanks. Don't "outsource" all of it to the fishes.

It's our responsibility to take the initiative and to perfect these skills...It's NOT our fishes' "job"- and that's for the benefit of all!

Stay compassionate. Stay thoughtful. Stay curious. Stay empathetic. Stay diligent. Stay engaged. Stay grateful...

And Stay Wet!


Scott Fellman

Tannin Aquatics

May 18, 2020


The "evolution" of our tanks isn't entirely under our control...and that's okay!

The idea of using leaves and botanicals in the aquarium to influence the function and/or aesthetics of the environment is not some "new" concept; indeed, hobbyists have been doing this in one form or another for many decades.

I think that what's different  is that we are now accepting the use of these materials for a combination of reasons- what we call "functional aesthetics"- the capability of a material to influence the look and the function of the aquarium environment simultaneously.

A real "mental shift..."

Some hobbyists have commented that, as their leaves and botanicals break down  the scape as initially presented changes significantly over time. Wether they know it or not, they are grasping "Wabi-Sabi"...sort of. One must appreciate the beauty at various phases to really grasp the concept and appreciate it. To find little vignettes- little moments- of fleeting beauty that need not be permanent to enjoy.


And, despite their impermanence, these materials function as diverse harbors of life, ranging from fungal and biofilm mats, to algae, to micro crustaceans and even epiphytic plants. Decomposing leaves, seed pods, and tree branches make up the substrate for a complex web of life which helps the fishes that we're so fascinated by flourish.

And, if you look at them objectively and carefully, these assemblages are beautiful.

This is not something new or previously unconsidered by the hobby, but it's something we don't give much thought to, I think. Of course, when we look at natural ecosystems where leaves and other botanical materials collect, the parallels in look and function become far more obvious!

Understanding the transient nature of botanical materials is absolutely essential for the botanical-style aquarium enthusiast. There are many who prefer a crisp, clean collection of botanicals and leaves in their tanks, and go to great effort to keep them that way...They will remove any leaf that starts to break down or recruit biofilms, and replace them with new ones. If you're up to the task- I say go for it!

For most of us- those of us who've made that mental shift- we let Nature dictate the evolution of our tanks. We understand that the processes of biofilm recruitment, fungal growth, and decomposition work on a timeline, and in a manner that is not entirely under our control.

Decomposition is an amazing process by which Nature processes materials for use by the greater ecosystem. It's the first part of the recycling of nutrients that were used by the plant from which the botanical material came from. When a botanical decays, it is broken down and converted into more simple organic forms, which become food for all kinds of organisms at the base of the ecosystem.

In aquatic ecosystems, much of the initial breakdown of botanical materials is conducted by detritivores- specifically, fishes, aquatic insects and invertebrates, which serve to begin the process by feeding upon the tissues of the seed pod or leaf, while other species utilize the "waste products" which are produced during this process for their nutrition.

In these habitats, such as streams and flooded forests, a variety of species work in tandem with each other, with various organisms carrying out different stages of the decomposition process.

We just plug along, feeding our fishes, doing water exchanges, and growing plants. We tend to our aquascapes, and watch things grow. And, over time, even the most diligently-maintained aquariums tend to look significantly different than when they did when they were first assembled.

It's how natural systems go.

There will be change. There will be decomposition.

If we allow it to happen. If we accept that some parts of the evolution of our aquariums are beyond our control.

Think about that!

Stay curious. Stay creative. Stay thoughtful. Stay bold...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


May 17, 2020


(Almost) everything I learned about life, I learned from my aquariums...almost!

I have come to one inescapable conclusion:

Everything I needed to know about life, I learned from my aquariums.

Ok, that sounds kind of insane, actually. And maybe it wasn't everything, but still...

Yet when you think about it, an aquarium can teach you a lot about life. Those little pearls of wisdom that we acquire as we play with our tanks can have real impact on the rest of our life.

Let’s look at these “lessons” a bit closer, and if you don’t agree- then you can tell me that I’m crazy!


Lesson One - Stay Focused -  When building and managing your aquarium, you’ll come to the realization that it’s hard to balance what you need to be doing with what you have the time, energy, and resources to actually do. Sure, you should be changing water every week, but you have that little distraction called life that may get in the way. And that’s okay. Your family, health, and relationships are more important than your aquariums. Yup. I just said it. Don’t lose focus on what’s really important. 

Focus on quality, not quantity in your tank management. Better to do a few things great than many things poorly. Seriously. Prioritize what needs attention more at certain times. Filtration? Algae scraping. Botanical replacement. Plant trimming? Things will ebb and flow and you can tackle every single one of your aquarium-keeping dreams and ambitions.

You just don’t need to do them all at the same time!

Or if you need to allot enough time.

Lesson Two- Practice Patience-  I know that in my personal life, I’d hardly be given the moniker of “patient”, but in my aquarium-keeping work, it’s my mantra!  Sure, like everyone else, I want a lush, colorful aquarium as quickly as possible. However, I found out the hard way through many years of aquarium keeping that the old cliche about not rushing things holds true. An aquarium is a biological microcosm, and it follows eons-old natural patterns of function and process. 

You can’t rush stuff. Oh, sure, you can “seed” your aquarium with biological material to speed up the cycling process, and you can grow your fishes ore plants  a bit faster with frequent water changes, feeding, and trace element replenishment...But it can only go so fast.

Besides, why would you want to rush it? 

Why not follow those good practices, but expect- and enjoy- a slower, more measured pace of growth in your tank? Botanical-style blackwater aquariums Patience is about understanding what steps it’s going to take to get you where you want to be, and measuring and evaluating your progress along the way. Eventually, you’ll get there. And you’ll probably find the journey every bit as enjoyable as the destination.

Trust me.



Lesson Three- Be an Authentic Aquarist - Huh? What I’m getting at here is that you should love being who you are as a aquarist!  Be comfortable in your own skin. Sounds like “psychobabble”, but it’s true!  In this social media-field era, it's more important than ever to do YOU. Your greatest aquarium-keeping successes will come when you practice being the type of hobbyist you are. Just because everyone is infatuated with Bettas and you love characins does not mean that you’re not a “cool” aquarist. There are so many angles to this hobby it isn’t even funny. Love what you specialize in, and share what you know with fellow hobbyists. 

And the authenticity part has further meaning...If you have no interest- or worse yet- no clue- about the long-term effects of botanicals in an aquarium  for example- then don’t get on the forums and start preaching the danger of biofilms and decomposition to fellow hobbyists based on what "someone said once", or whatever. What I call “regurgitation”- the act of ranting authoritatively about stuff you may have heard of but have not practiced- is really unhelpful to the rest of the aquarium world. It doesn't offer the value of knowledge gained from personal experience, and the nuance that goes with it.

In our sector it's how myths like "leaves can soften water" got started. Be proud of your aquarium, your experience, and the type of aquarist that you are. Maybe you don't know the answer for are from personal experience. Nothing wrong with that. However, don't give "advice" that you can't back up with first hand experience, unless you're specifically noting that you're passing along second or third hand information.

Sure, some stuff, like, "Don't add household bleach to your tank" is an experience you've likely never had personally, but it makes sense to share. Yet, in general, when giving advice, make it about your personal experience  It's more helpful that way.Share selflessly, but play to your strengths. Push yourself, evolve, adapt, flow. But above all, be yourself. 

Lesson Four- Count on Your “Peeps” -  It’s crucial to have other fish geeks to turn to when things get tough. Sure, you can be a free-thinking aquarist, but don’t go it alone. You’re not an island. Reach out on the forums and at local clubs and to your LFS and consult other hobbyists. Not only will you learn more and have a good time with your hobby- you might just end up making lifelong friends! Build relationships, and seek out friends, experts and cheerleaders when you need them. It’s a smarter, more effective way to succeed in the hobby.

Join the local aquarium club, or start one if there isn’t one in your area. Hang out at your local fish store and support it in every way-now, more than ever. It’s the literal “watering hole” for your local hobby experience. Not only will you be supporting a good cause (your local brick and mortar store), you’ll be making valuable aquarium-keeping connections that will provide you with great pleasure. Of course, you can join one of the many friendly aquarium communities online, and connect with fellow fish geeks all over the planet. Cultivating friendships is a great little investment in your hobby-and your life- that will pay huge dividends down the line.


Lesson Five- Learn to...Stop - Apparently, Im not alone: Many fish geeks just never learned how to say no gracefully! This is evidenced by the many 120-gallon aquariums containing every conceivable type of fish, plant, or coral known to the hobby! I see this in the reef end of the hobby a lot! This is a real problem, too, as it can lead to an overcrowded, biologically mismatched aquarium population at best (do a Google search on “allelopathy”), and total disaster at the worst! The solution is to excercise restraint. Just say “NO” sometimes!

Of course, you can always get another aquarium at some point (the whole “Multiple Tank Syndrome” experience) if you want to try keeping widely divergent animals together without bloodshed. You just don’t want to go down this path, adding every conceivable animal to your aquarium. If you’re so busy saying “yes” to all of the wrong animals, when are you going to have the space for the right ones when they come along? 


Lesson Six- Face Your Fears -   Shit, just get out of your comfort zone once in a while! I’m not saying to try to set up a 400 gallon non-photosynthetic coral aquarium just to prove that you’re a badass...What I am saying is that you should try something different from the tried-and true sometime. Keep that slightly-less-than-super-hardy wild Betta species if you have the hunch that you can do it. Great things can happen when you push through the fear.

Put your experience, intuition, and observational powers to the test. Try the strange, leaf-litter -only tank. Use that different type of wood that you've been rolling over in your next scape. Maybe might be the first person to breed that weird little Hatchet Fish that you have a secret fetish about. You may be the one person that figured out how to keep that uber-delicate deepwater Acropora alive and thriving.

I’m not advising you to gamble with the life of a helpless animal in order to "vanquish your fears." What I'm suggesting is that you should play the occasional hunch and push yourself a bit. If it weren’t for the brave folks like many of my former colleagues in the coral-propagation world, we would probably just now be realizing a viable market for commercially-propagated coral.

If someone like Jack Wattley didn’t take a chance trying to breed dozens of varieties of Discus, we might be stuck with wild-imported specimens as our only  option (not that there is anything wrong with the wild types, mind you!). When you feel you are capable - take a chance. The benefits to you- and to the hobby- might be incalculable.

Lesson Seven- Lighten Up! -  You heard me! Have some fun! This hobby is not supposed to be a peer-pressure-ridden pressure cooker with impossible-to-meet challenges and goals. You aren’t required to have a perfect aquascape that some self appointed “hobby demigod” would approve of. You don’t need to be doing all of the same things that the guy in Holland with a 29,000 liter aquarium is doing. You don’t, and you probably can’t - so why sweat it? Maybe your taste is a little different...

Enjoy your aquarium, no matter what size, what type of animals you keep, and how it looks.  Laugh at the fact that you get all worked up about little red bugs on your corals, or that you purchase and boil leaves from a company called Tannin Aquatics  

You likely keep stinky frozen worms and stuff in your freezer, right next to the Haagen-Dazs! Take pride in the fact that you are one of a select group of people that keep some of nature’s most amazing creatures alive outside of their natural habitat. Not only alive- but thriving! 

And you do it in a way that more closely resembles Nature as it IS than almost any other hobby group.

And that means something to many of us, doesn't it?

When you screw up- and you will - accept the consequences with grace and humor. Laugh about it. Share the mistakes and foibles with fellow fish geeks. You’re probably not the only one who nuked his or her aquarium with unwashed silica sand, unleashed a "small" pike cichlid into your peaceful tank fo " tough" characins, or placed a Galaxea two inches from your prized Sunset Montipora. so smile...That which doesn’t kill our enthusiasm for the hobby makes us a better hobbyist.

Perhaps less financially solvent- but better for the journey, nonetheless!

My hope here is that you realize that an aquarium is not just a pleasant diversion; a fun hobby- it can be a lifelong passion, a teaching tool for the entire family. And perhaps, most underrated of all - a reef aquarium can serve as a beautiful classroom for some of the larger mysteries of life.

It sounds almost bizzare, but I believe it to be true when I say that everything I needed to know about life, I learned from my aquairums. Ok, almost everything. I never really figured out how to get my dog to listen to me. And how to do those little Chinese finger puzzles, or how to flip pizza dough, or...

Yeah, a lot to learn.

Enjoy the process.

Stay unique. Stay bold. Stay excited. Stay engaged...

And Stay Wet.


Scott Fellman

Tannin Aquatics 





May 15, 2020


The changing of the season...Stuff we learned from Corys...

Every Corydoras breeder knows something that we all should know:

Environmental manipulations create unique opportunities to facilitate behavioral changes in our fishes.

It's hardly an earth-shattering idea, but I think that the concept of seasonal environmental manipulation deserves some additional consideration.

It's been known for decades that environmental changes to the aquatic environment caused by weather (particularly "wet" or "dry" seasons/events) can stimulate fishes into spawning. 

As a fish geek keen on not only replicating the look of our fishes' wild habitats, but as much of the "function" as possible, I can't help myself but to ponder the possibilities for greater success by manipulating the aquarium environment to simulate what happens in the wild.

Probably the group of aquarists who has had the most experience and success at incorporating such environmental manipulations into their breeding procedures is Corydoras catfish enthusiasts! 

Many hobbyists who have bred Corydoras utilize the old trick of a 20%-30% water exchange with water that is up to 10° F cooler (6.5° C) than the aquarium water is normally maintained at. It seems almost like one of those, "Are you &^%$#@ crazy- a sudden lowering of temperature?"

However, it works, and you almost never hear of any fishes being lost as a result of such manipulations.

I often wondered what the rationale behind such a change was. My understanding is that it essentially is meant to mimic a rainstorm, in which an influx of cooler water is a feature. Makes sense. Weather conditions are such an important part of the life cycle of our fishes.

Still others attempt to simulate a "dry spell" by allowing the water quality to "degrade" somewhat (what exactly that means isoprene to interpretation!), while simultaneously increasing the aquarium temperature a degree or two. This is followed by a water exchange with softer water (ie; pure RO/DI), and resetting the tank temp to the tank's normal range of parameters.

The "variation" I have heard is to do the above procedure, accompanied by an increase in current via a filter return or powerhead, which simulates the increased water volume/flow brought on by the influx of "rain."


Many breeders will fast their fishes a few days, followed by a big binge of food after the temperature drop, apparently simulating the increased amount of food in the native waters when rains come.

Still other hobbyists will reduce the pH of their aquarium water to stimulate breeding. And I suppose the rationale behind this is once again to simulate an influx of water from rain or other external sources...

Weather, once again.

And another trick I hear from my Cory breeder friends from time to time is the idea of tossing in a few alder cones into the tank/vessel where their breeders' eggs are incubating.

This decades-old practice is justified by the assertion that the alder cones possess some type of anti-fungal properties...not entirely off base with some of the scientific research we've found about the allegedly anti-microbial/antifungal properties of catappa leaves and such...

And of course, I hear/read of recommendations to use the aforementioned catappa leaves, oak leaves, and Magnolia leaves for just this purpose...


And of course, if we look at the natural habitats where many of our fishes originate, we see these seasonal changes having huge impact on the aquatic ecosystems. In The Amazon, for example, the high water season runs December through April.

And during the flooding season, the average temperature is 86 degrees F, around 12 degrees cooler than the dry season. And during the wet season, the streams and rivers can be between 6-7 meters higher on the average than they are during the dry season! 

And of course, there are more fruits, flowers, and insects during this time of year- important food items for many species of fishes.

And the dry season? Well, that obviously means lower water levels, higher temperatures, and abundance of fishes, most engaging in spawning activity. 

Any annual or semi-annual killifish species enthusiast will tell you a dozen ways to dry-incubate eggs; again, a beautiful simulation of what happens in nature...So much of the idea can be applicable to other areas of aquarium practice, right? 

Yeah... I think so.

It's pretty clear that factors such as the air, water and even soil temperatures, atmospheric humidity, the water level, the local winds as well as climatic variables have profound influence on the life cycle and reproductive behavior on the fishes that reside in these dynamic tropical environments! 

We've literally scratched the surface, and the opportunity to apply what we know about the climates from where our fishes originate, and to incorporate, on a broader scale, the practices which our Corydoras-enthusiast friends employ on all sorts of fishes.

So much to learn, experiment with, and execute on.

Stay fascinated. Stay intrigued. Stay observant. Stay creative. Stay astute...

And Stay Wet.


Scott Fellman

Tannin Aquatics