The "why?" part of the botanical equation, and the importance of our firsthand observations...

As we move further along on the path towards enlightenment in the world of botanical-style aquariums, I am constantly thinking about the "how's and why's" of what we do. 

Now, we have evolved a lot in our "technique"- you know, stuff like how to prepare botanical materials, the pace at which we add them, how to gauge the impact of these additions, etc.

And, of course, we are also getting pretty good at accepting and understanding the progression of what happens in these aquariums- you know, the formation of biofilms, the tinting of the water, and their ultimate decomposition. We are going beyond just looking at these things and freaking out, and attempting to understand what causes these things, how they form, and- most important- what benefits they can bring to our aquariums.

One of the questions which I am often asked by the uninitiated is, "Why do you add this stuff to your aquariums?" A truly foundational question, of course- one which literally makes us think through the entire process.

Obviously, we could go into the answer in great detail, but I think that we've more or less covered the "why?" part of the equation since day one in this column, so I won't go on and on about that. Suffice it to say, we play with botanicals in our aquariums because they help us to replicate- in some manner, the processes and conditions which occur in natural aquatic systems. 

It's as simple- and complex- as that.

It's all about replicating the look and function of Nature, and most important- helping to understand why.

And the most important thing is not to get too far out in front of this stuff and make assumptions. Although we can replicate some aspects of Nature, we don't have the technical means, at least at a hobby level, to verify all of the impacts of utilizing botanical materials in our aquariums. To that end, you'll notice that, in this column and elsewhere, you won't see us making wild, broad assertions about what botanicals can and cannot do in aquariums.

We can report upon the impacts that we can see and quantify in our aquariums, and research the potential impacts that these materials have. We can also study the botanical materials which accumulate in natural aquatic habitats, and attempt to understand their influences on them. We can ask questions, entertain hypothesis, and experiment.

However, we don't make assertions about them, and we discourage our community not to, either. We can't- we shouldn't. 

I hate exaggerations, the perpetuation of myths, and the attribution of capabilities to techniques, products, etc. in the hobby which are only marginally based in fact. Especially when these ideas are pushed out by people who may not have all of the facts, the personal experience, and/or the background to back it up. 

These things become very detrimental to the hobby.

Now look, I realize that many of these things are offered up with very good intentions; not with some "nefarious purpose" in mind. I mean, sure, sometimes you'll see someone who has a vested interest in selling something proffer these kinds of things, which flat-out sucks. I think it's far more beneficial in the long run, to simply acknowledge that they don't have 100% certainty about the benefits of their product, but that there are interesting results and potential benefits, and to encourage responsible experimentation.

That's the lane we've operated in, and it's led to a tremendous amount of participation and good information being created for the hobby. We as a brand and us as a community share our success, challenges, and outright failures openly. We all learn together. We don't simply "parrot each other"-regurgitating secondhand information- and that's great!

Unfortunately, in the aquarium hobby, it's not uncommon to see straight-up "regurgitations" by otherwise well-intended hobbyists, making strong assertions or statements about this stuff- good or bad- who simply didn't bother to do their "due diligence" and research the facts for themselves before pushing it out on the web with personal commentary. Often, these people have no firsthand knowledge or experience with the stuff they are pushing out! You know, the aquarium equivalent of "re-tweeting" something just because.

Well, that sucks, too. Right?

It sucks because it doesn't really add to the body of knowledge we are trying so hard to accumulate. It sucks because it can perpetuate second-hand knowledge that may or may not be accurate.

As a guy who sells leaves and botanicals for a living, I've had to be careful to not regurgitate the observations of others without personal verification, or  ascribe miraculous attributes to the stuff I sell- because it's not only not helpful- it can be downright misleading- and certainly counterproductive for the hobby and industry by doing so!

And I see a lot of counterproductive garbage being put out there about leaves and botanicals at scale. It's important to address some of this stuff from time to time, especially when it's about our use of botanicals in natural-style aquariums. We have an obligation, of sorts, to elevate our practice of utilizing natural materials in aquariums, and that often means diving just a bit deeper when seemingly "too good to be true" assertions are made. 

Here is one of the most common misunderstood "botanical claims":

Catappa leaves can "cure fish diseases."

This is one which has been perpetuated for years (often by people who sell leaves online and elsewhere).

It bothers me.

Although, it actually has some validity to it. I said "some" validity- because we in the hobby and industry tend to selectively "cherry pick" stuff we like from science and run with that, often overlooking some of the more sobering realities in favor of the "sizzle."


Clarification is required. 

It has been known for many years by science that botanicals like catappa leaves (and others) do have compounds in their tissues which do have some potential "medicinal" functions; compounds like saponins, phytosterols, punicalagins, etc.  Fancy names that sound really cool- these compounds found in Catappa leaves are often bounced around on hobby sites as the "magic elixir" for a variety of fish ailments and maladies.

That's where the danger of regurgitation sneaks in.

Now, I can't entirely beat the crap out of this idea that Catappa leaves have some health benefits for fishes, as these compounds are known to provide certain health humans.  Homo spaiens... And for a long time, it was anecdotally assumed that they did the same for fishes. Now, sure, humans aren't fishes, as we all know...Yet, believe it or not, there have been some studies that show benefits to fishes imparted by substances in Catappa and other leaves.

I stumbled across a university study conducted in Thailand with Tilapia which concluded that a Catappa extract was "useful" for eradicating the nasty exoparasite, Trichodina, and found that the growth of a couple of strains of Aeromonas hydrophila was also inhibited by dosing Catappa leaf extract at a concentration of 0.5 mg/ml and up. In addition, this solution was shown to reduce the fungal infection in Tilapia eggs!

And it is now widely accepted by science that humic substances (such as those present in Catappa leaves and other botanical materials) are thought to have a wide range of health benefits for fishes in all types of habitats. We've covered this before in a great guest blog by Vince Dollar, and the implications for the hobby and industry are profound. Although they are not the "cure all" that many vendors have touted them as, leaves and other botanicals do possess a wide range of substances which can have significantly beneficial impact on fish health.


So, these claims are not entirely erroneous; however, it's important NOT to make over-inflated assumptions about Catappa, and to assume that they are "miraculous things" that we can add to our tanks to do achieve smashing success at curing sick fishes. Just because we add leaves and such to our tanks, doesn't mean that they are imparting therapeutic benefits to our fishes. 

The studies involved an extract of catappa leaves at a specific dosage- a lot more "precise" than simply tossing some leaves into a tank, right?

Rather, I would imagine that, as Catappa leaves and other botanical materials break down in our aquariums, they impart some of these beneficial compounds into the water, perhaps fostering a more healthy environment for fishes which are accustomed to blackwater conditions. Perhaps they perform an almost "prophylactic" role at preventing disease and supporting overall fish health, as opposed to functioning as some sort of "cure all." 


And that leads to questions, of course:

What "dosage" do we apply? How many leaves steeped in how much water yields a concentrated solution of 0.5 mg/ml or more? How long do these materials need to be in the aquarium to accomplish this? And is there truly some measure of effectiveness?

We're learning the answers to some of these questions as a community, aren't we? I think so, but we still cannot say with 100% certainty that it's the botanicals in our aquariums which can cause all of the positive benefits which our community has reported with botanical-style aquariums.

Breaking through the barrier of assumptions, market hyperbole, and fluff that has often clouded this tinted world before we all came together and made a real effort to understand the function as well as the aesthetics of this dynamic, engrossing hobby niche will only benefit the hobby as a whole.

Let's keep working together to push the state of the hobby farther than ever, backed up with facts and personal experiences! When we aren't sure about something, there is absolutely no shame in saying, "We're just not sure..."

Everybody wins that way.

And there is something really interesting about our "work." 

There's been a fair amount of research and speculation by both scientists and hobbyists about the processes which occur when terrestrial materials like leaves and botanical items enter aquatic environments, and most of it is based upon field observations by scientists and ecologists.

As hobbyists, we have a unique opportunity to observe firsthand the impact and affects of this material in our own aquariums! I love this aspect of our "practice", as it creates really interesting possibilities to embrace and create more naturally-functioning systems, while possibly even "validating" the field work done by scientists! It goes without saying that there are implications for both the biology and chemistry of the aquatic habitats when leaves and other botanical materials enter them.

Many of these are things that we as hobbyists observe every day in our aquariums! This is where it gets pretty interesting.

Here's an interesting example of making "home aquarium field observations" based upon work done by scientists:

It's about our old nemesis, biofilm.

A lab study I came upon found out that, when leaves are saturated in water, biofilm is at it's peak when other nutrients (i.e.; nitrate, phosphate, etc.) tested at their lowest limits. This is interesting to me, because it seems that, in our botanical-style, blackwater aquariums, biofilms tend to occur early on, when one would assume that these compounds are at their highest concentrations, right? And biofilms are essentially the byproduct of bacterial colonization, meaning that there must be a lot of "food" for the bacteria at some point if there is a lot of biofilm, right?

More questions...

Does this imply that the biofilms arrive on the scene and "peak out" really quickly; an indication that there is actually less nutrient in the water column? Is the nutrient bound up in the biofilms? And when our fishes and other animals consume them, does this provide a significant source of sustenance for them?


What are the implications of biofilms as a sort of "nutrient export mechanism?"

Oh, and here is another interesting tangential observation which scientists made in a study I stumbled upon:

When leaves fall into streams, field studies have shown that their nitrogen content typically will increase. Why is this important? Scientists see this as evidence of microbial colonization, which is correlated by a measured increase in oxygen consumption. This is interesting to me, because the rare "disasters" that we see in our tanks (when we do see them, of course, which fortunately isn't very often at all)- are usually caused by the hobbyist adding a really large quantity of leaves at once, resulting in the fishes gasping at the surface- a sign of...oxygen depletion?

Makes sense, right? 

These are interesting clues about the process of decomposition of leaves when they enter into our aquatic ecosystems. They have implications for our use of botanicals and the way we manage our aquariums. I think that the simple fact that pH and oxygen tend to go down quickly when leaves are  initially submerged in pure water during lab tests gives us an idea as to what to expect.

A lot of the initial environmental changes will happen rather rapidly, and then stabilize over time. Which of course, leads me to conclude that the development of sufficient populations of organisms to process the incoming botanical load is a critical part of the establishment of our botanical-style aquariums.

Obviously, this is a hypothesis which directly impacts our practices and techniques. One could say that I'm "cherry picking" this stuff from scientific literature. True, but I'm "cherry picking" it not because it supports some narrative of mine. Rather, it opens up the opportunity to correlate things which happen in the wild habitats with those which happen in our aquariums.

Exploration and consideration- two important endeavors.

The topics mentioned here are just a few of the many interesting ones that we can explore as hobbyists- helping to advance the state of the art of botanical-style aquariums, and dispel some of the regurgitated "myths" that seem to abound. 

By moving forward in a measured manner, and sharing our firsthand experiences freely, we create a vibrant, exciting area of the hobby, where everyone who participates can add to the amazing body of knowledge.

Stay involved. Stay curious. Stay open-minded. Stay honest. Stay diligent. Stay excited...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


Scott Fellman
Scott Fellman


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