The practice of "functional diversity" in the aquarium

In the aquarium game, we're able to control a lot of things in the little worlds we create. You know, the temperature, pH, food, water movement, etc. We put a lot of emphasis on creating "appropriate" environments for the animals that we keep. And we do a great job! In my opinion, we intentionally do this and create what I like to say are "95% effective" systems. And although it sounds that way, it's not meant to be an indictment or "diss" in any way. It's sort of an opinion of mine based on a specific observation:

We're missing the intentional deployment of one concept: Diversity. The one thing that we seem to not practice "intentionally" is diversity of the aquarium environment. 

In my opinion, one of the most important things that we can do for the long-term health of our fishes is to create some diversity.

Yeah, diversity. 

Now, I'm not talking about the "I-have-14-different- Pseudotropheus zebra-morphs" kind of "diversity." We do a pretty good job at that. I'm thinking a little differently here. We're talking about the diversity of the entire microcosm that you've created in your aquarium.

What strikes me most about many of the most successful aquariums I've seen is their refreshing diversity. They feature a complete range of life forms, such as fishes, plants, and even invertebrates. Just like in nature, these systems incorporate life forms that provide beneficial collateral benefits for their inhabitants, such as food, shelter, and nutrient export.  Well-stocked community aquariums are beautiful systems that are a visual delight, affording many opportunities to see examples of the endless variety of aquatic life forms.

And they offer what I call "functional diversity."

The "diversity" applies not only to the life forms in the aquarium in this context, it also applies to the materials that we use to appoint the tank- Like botanicals, leaves, wood, even rocks. In my opinion (and some of it is backed by legit research!), it's beneficial to the inhabitants of a botanical-based aquarium to utilize a number of tannin and humic-substance-producing materials in our aquascapes.

This gives you some good "coverage", in terms of the types of substances imparted. As we are learning, humic substances are very important- perhaps even crucial-to fish health. And since no definitive study identifying exactly what specific humic substances are best, and are released by which botanicals is available, the best thing we can do at this point is to deploy as wide a variety of them as possible.

This is in many ways analogous to the natural habitats of our fishes, isn't it?

I mean, so many things influence the aquatic environment, from soils to tree branches, to seed pods, and of course, leaves, that it's only logical, in my mind, to replicate this component of the wild habitats of our fishes, even if we're "shooting blind" here a bit. There is a reason why habitats such as the Rio Negro are so successfully populated by a variety of fishes, and one can't help but draw the most simple conclusion as to why- it's because they offer the most appropriate and consistent parameters for their inhabitants, which have evolved over time to thrive in them.

And by having a wide variety of materials in our aquascapes as the structural, aesthetic, and functional foundations of our aquariums, we're truly creating a more faithful representation of the natural environment. It all starts with diversity.

Diversity. On many levels. It works. We've been doing it, most of the way, for generations. We've been practicing "functional diversity" with reef aquariums for several decades (you know, live rock, live sand, corals, inverts, macroalgae). Now it's time to sort of "up our game" even more, and make a more conscious effort to practice it in all of our aquariums.

Blackwater, botanical-themed aquariums can lead the charge towards "functional diversity" in the freshwater genre, because we're supplying not only the beneficial humic substances which fishes require, but we're helping create a foundation for a food web, with decomposing botanicals, biofilms, fungi, and of course, the animals which feed on them. We don't see this practiced with the same intent in other freshwater "methodologies", with the possible exception of planted aquariums, which, through use of soil additives and fertilizers, create nutritious and "active substrates" for plants.

We can do the same for our fishes. Can you imagine being able to add "pure", pathogen-free cultures of aquatic insects (okay, not mosquitoes and flying "yucky" kinds, lol) and crustaceans to our aquariums from different regions- say, Amazonia or Asia, which help break down the leaves, consume fungi, and supplement the diets of our captive fishes? Conceptually, we can do this right now...the opportunities for experimentation, implementation, and even commercial exploitation are there!

The mid 21st century may very well see the implementation of exotic concepts, like "crustacean reactors", automated wingless fruit fly dispenser systems, or "food-web-specific freshwater refugiums." (Tip- for some inspiration, check out some of the more esoteric reef information from the early 2000's!)

That's some "next level shit", as one of my fishy friends would say.

And it starts with embracing the idea of "functional diversity" in the aquarium environment; thinking about what it means and how it applies to what we do. And guess what, as a "practitioner" of the "Blackwater/New Botanical-style" aquarium, you're already most of the way there. That "mental shift" we've talked so much about here in regards to these types of aquariums has set you up nicely to explore the "bleeding edge" of aquarium practice, hasn't it?

Take a deep breath, pat yourself on the back for just a second, and then roll up your sleeves and think about how to further develop and employ this concept.

Welcome to the frontier. Kind of nice out here, isn't it?

Stay focused. Stay creative. Stay relentless.

And Stay Wet.

Scott Fellman

Tannin Aquatics






Scott Fellman
Scott Fellman


2 Responses

Scott Fellman
Scott Fellman

December 17, 2016

Hey Kim,

Glad you enjoyed! I think the important point is to get a real good understanding of the basics of aquarium husbandry and practice down. Experience a few of the variable and ups and downs of maintaining an aquarium for a while, and then push outwards to try new things…You hit it on the head…just enjoy and don’t worry about the boundaries just yet. Over time, they’ll become more obvious to you, and as you gain more confidence and experience, you’ll know in which direction you want to move! Enjoy!



December 16, 2016

A very exciting read! Makes me want to rush right out into the cold to forage for even more natural things to add to my angels’ tank but I’m still fairly new to the aquarium game and nervous about pushing the boundaries when I’m not yet even sure where they are.


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