Under the influence...


It's fun to speculate on how the materials we incorporate into our aquariums can change the environment within them.

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

I mean, on the surface, this is not a revolutionary idea...We've been doing stuff like this in the hobby for a while- more crudely in the fish-breeding realm (adding peat to water, for example...), or with aragonite substrates in Africa Rift Lake cichlid tanks, or with mineral additions to shrimp habitats, etc.

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

So, it pretty much goes without saying that the idea that utilizing different types of botanical materials in the aquarium can likely yield different effects on the water chemistry, and thus impact the lives of the fishes and plants that reside there- is not that big of a "stretch", right? I can't help but wonder what the possible impacts of different leaves, or possibly even seed pods from different geographic areas can have on the water and overall aquarium environment.

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

Could utilizing different combinations of botanicals in aquariums potentially yield different environmental results? In the future, will this lead to the potential  development of step-by-step "recipes" for creating various types of physiological reactions in fishes?  You know- scenarios like, "Add this if you want fishes to color up. Add a combination of THIS and THIS if you want the fishes to commence spawning behavior", etc.

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

Absolutely not, IMHO.

I think the main thing which keeps the idea from really developing more in the hobby- knowing exactly how much of what to add to our tanks, specifically to achieve "x" effect- is that we as hobbyists simply don't have the means to test for many of the compounds which may affect the aquarium habitat. We aren't even 100% certain which compounds are present in many natural habitats, right? Assays would have to be completed on wild aquatic habitats to determine this.

In addition, we'd have to sift through a lot of field research on the physical characteristics and water chemistry of the habitat of various fishes to see which compounds influence which specific behaviors or impart specific health benefits, right?

Tons of variables.

At this point, it's really as much of an "art" as it is a "science", and more superficial observation- at least in our aquariums- is probably almost ("almost...") as useful as laboratory testing is in the wild. Even simply observing the effects upon our fishes caused by environmental changes, etc. in the aquarium by our experiments is useful to some extent.

At least at the present time, we're largely limited to making these sort of "superficial" observations about stuff like the color that a specific botanical can impart into the water, the reactions of our fishes to the tinting, etc.

It's a good start. 

As hobbyists, we tend to make assumptions, which can sometimes be problematic. I mean, we've pretty much beaten the living shit out of the idea that, just because the water in your aquarium is brown, it doesn't mean that you have soft, acidic "Amazonian" conditions. So, admittedly, we in the hobby have to "up our game" a bit rather than make such assumptions based on something like the color of the water!

Of course, not everything we can gain from this studying is superficial...some botanical materials actually do have some scientifically confirmed impacts on the aquarium environment. And yeah, they DO happen to color up the water, right?

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

Of course, I Say "infer" because, even though these compounds have been determined to be present in catappa leaves, how can we be sure that they are leaching into the water in our aquariums, and at what concentration? It's a guessing game at best; what we can do is operate on the assumption (gulp) that some of this stuff is getting into our tank water.

An assumption that our aquariums are "under the influence" of botanicals! 

When we first started Tannin, I came up with the term "habitat enrichment" to describe the way various botanicals can impact the aquarium environment. I mused on the idea a lot. (I know that doesn't surprise many of you, lol...)

Now, I freely admit that this term may easily be interpreted as much more of a form of "marketing hyperbole" than it is a technical description of what occurs when we add botanicals to our tanks. However, I believe that the idea sort of resonates, when we think of the aquarium as an analog for the wild aquatic habitats, and how the surrounding environment- the terroir- impacts the aquatic environment, right?

Wine, for example, has "terroir"- a concept which acknowledges that the environmental conditions, especially soil and climate, in which grapes are grown  give a wine its unique flavor and aroma... and coffee also acquires traits that are similar. Tangible effects and characteristics, which impact the experience we get from them.

Tangible effects.

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

I think that there is "something" to this.

Sure, a good number of these interesting events and effects could likely be written off as mere "coincidences"- but when it happens over and over and over again in this context, I think it at least warrants some consideration! 

I mean, there is something to it all, huh?

We're slowly beginning to figure this stuff out. We as aquarists often walk the line between amateur scientists/sleuths and artists.

Yeah, we’re artists. But we're more than that, too:

Mad scientists.

Fish geeks.


Yeah, artists.

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

There is so much we don’t know yet. Or, more specifically, so much we don’t know in the context of keeping fishes. We need to tie a few loose ends together to get a really good read on this stuff…until we get to the "Dial-a-River” additive stage ("Just add a little of this and a bit of that, and...".) that I talked about earlier.

But we're getting there...At least in terms of understanding some of the tangible benefits of botanical use, besides just the aesthetics. It's a slow, often tedious process, requiring us to do more than simply make assumptions. It often involves a lot of amateur sleuthing through relevant scientific literature, hoping to extract some kernels of wisdom.

I think we're starting to see a new emergence of a more "holistic" approach to aquarium keeping...a realization that we've done amazing things so far, keeping fishes and plants in a glass or acrylic box with applied technique and superior husbandry...but that there is room to experiment and push the boundaries even further, by understanding and applying our knowledge of what happens in the real natural environment. 

You're making mental shifts...replicating Nature in our aquariums by achieving a greater understanding of Nature...studying and attempting to replicate different components of the natural habitats of our fishes than we have previously- like substrate. 

Yeah, we've opened up a whole new can of worms with the idea of functional substrates for botanical-style aquariums, haven't we? At least, I hope that we have! The substrate is one of the more overlooked aspects of the aquarium, IMHO. The substrates in wild aquatic habitats have so much more to do with the environment than we think that they do.

One study concluded that the Rio Negro is a blackwater river in large part because the very low nutrient concentrations of the soils that drain into it have arisen as a result of "several cycles of weathering, erosion, and sedimentation." In other words, there's not a whole lot of minerals and nutrients left in the soils to dissolve into the water to any meaningful extent!


This fascination I have about the relationship between aquatic and terrestrial ecosystems led me down the path of creating and experimenting with a new (for aquariums, anyways) class of substrate materials which I call "sedimented substrates", composed of a number of materials, including clays and sediments, which were intended to influence the aquatic habitat in "fish-centric" botanical-style aquarium systems.

Let's touch on them for a little bit, because I do receive a lot of questions about them from our community. 

First off, let me make it clear these substrates were originally intended for a very specific purpose: To replicate the terrestrial soils which are seasonally inundated in the wild. As such, they were compositionally different than typical aquarium substrates. This also means that they "behave" differently when used in our aquariums in a number of ways.

Like, they will make your water cloudy at first.

Scared yet? I hope not. Because, as it turns out, they are useful and interesting for all types of aquariums, not only the ones which replicate flooded forest and grassland habitats.

Why are they comprised of sediments and clays? 

Well, for one thing, sediments are an integral part of the natural substrates in the habitats from which our fishes come. So, they're integral to our substrates. In fact, I suppose you'd best classify our NatureBase substrate products as "sedimented substrates."

Now, think about it. These materials have profound influence on the aquatic habitats in which they are found. Many of our favorite habitats are forest floors and meadows, which undergo periodic flooding cycles in regions like the Amazon, which results in the creation of aquatic habitats for a remarkable diversity of fish species.

Depending on the type of water that flows from the surrounding rivers, the characteristics of the flooded areas may vary. An important impact is the geology of the substrates over which the rivers pass. This results in differences in the physical-chemical properties of the water. In the Amazon, as we've talked about for years here, areas flooded by rivers of black or clear waters, with acid pH and low sediment load in addition to being nutritionally poor, are called “igapó."

This transition from terrestrial to aquatic results in a very unique ecology, worthy of our study as aquarists. It's a fascinating dynamic, weaving together ecology, biology, botany, and geology.

The flooding ("inundation") often lasts for several weeks or even several months, and the plants and trees need special biochemical adaptations to be able to survive the lack of oxygen around their roots during this period. 

Another interesting ecological adaption: During the inundation period, many of the forest trees drop their fruits into the water, where they are eaten by fish. As an interesting side note, ecologists have noted that some of these trees and plants are strongly dependent on the fishes to disperse their seeds through the forest, requiring that the seeds pass through the gut of a fish before it will germinate.


Fishes which consume matter found in the substrate (detritivores) and other materials in the substrate (omnivores) also play a fundamental role in the transportation of organic carbon, which is a source of energy for downstream fish communities. Through their foraging activities, these fishes enhance the "downstream transport" and processing of organic material and ensure the proper functioning of the aquatic system and its biological community.

So, we have the terrestrial environment influencing the aquatic environment, and fishes that live in the aquatic environment influencing the terrestrial environment!

Forest floor soils in tropical areas are known by soil geologists as "oxisols", and have varying amounts of clay, sediments, minerals like quartz and silica, and various types of organic matter. So it makes sense that when flooded, these "ingredients" will have significant impact on the aquatic environment. This "recipe" is not only compositionally different than typical "off-the-shelf" aquarium sands and substrates- it looks and functions differently, too. (ie; the initial turbidity)

And that's where a lot of people will metaphorically "leave the room."

So, yeah, you'll have to make a mental shift to appreciate a different look and function. And many hobbyists simply can't handle that. We're being up front with this stuff, to ward off the, "I added NatureBase to my tank and it looks like a cloudy mess! This stuff is SHIT!" type of emails that inevitably come when people don't read up first before they purchase the stuff.

And it just so happens that these products actually grow aquatic plants...pretty well, too! 

Okay, enough of the mini "infomercial" on our substrates. The concept of influences of external factors on our aquariums is super cool.

Land and water, working together, provide an amazing resource for the adventurous and interested hobbyist to explore in greater detail. These regions are diverse harbors of life, ranging from fungal and biofilm mats, to algae, to epiphytic plants. Decomposing leaves, seed pods, and tree branches compose the substrate for a complex web of life which helps the fishes we're so fascinated by flourish. And, if you look at them objectively and carefully, they are beautiful.

I think the botanical-style aquarium community can create a model for hobby-level contribution to the body of knowledge about these highly fascinating, remarkably diverse, surprisingly pervasive, and incredibly compelling natural aquatic habitats.  

As an aquarist, a little bit of faith in the natural process, and a willingness to let go of your preconceptions of exactly what an aquarium should look like- is absolutely necessary.

Even mandatory.

Once you free your mind of  these "prejudices", you will really begin to accept and appreciate the natural beauty of what these systems are all about. To understand the influence of all sorts of ecological factors upon the aquatic environment. To be willing to embrace these influences to create compelling, functional representations of some of the more unusual aquatic habitats of the world.

Hobbyists who incorporate botanicals and such into their aquarium nowadays are looking at things more "holistically', embracing the natural processes, such as the breakdown of materials, accumulation of biofilms, and even the occasional spot of algae, as part of the environment to be studied and enjoyed, rather than to be loathed, feared and removed.

We're learning more about the interactions between our fishes and these unique environments, and the opportunities to gain and share this new knowledge are endless! I think just having a bit more than a superficial understanding of the way botanicals and other materials influence and interact with the aquatic environment, and how we can embrace and replicate these systems in our own aquariums is really important to the hobby.

The real message here is to not be afraid of learning about seemingly complex chemical and biological nuances of aquatic ecosystems, and to apply some of this knowledge to our aquatic practice.

I also have this irresistible curiosity about the potential of botanical-influenced aquariums to foster a unique and complex ecology in our aquariums. With the diverse assemblage of microorganisms and a continuous food source of decomposing botanicals "in house", I can't help but think that ideas like "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."

Stay thoughtful. Stay resourceful. Stay creative. Stay studious...

And Stay Wet.


Scott Fellman

Tannin Aquatics 



Scott Fellman
Scott Fellman


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