"Project 18": The turning point.

In Amazonian blackwater rivers, studies have determined that the aquatic insect abundance is rather low, with most species concentrated in leaf litter and wood debris, which are important habitats.  Yet, here's how a food web looks in some blackwater habitats : Studies of blackwater fish assemblages indicated that many fishes feed primarily on burrowing midge larvae (chironomids, aka "Bloodworms" ) which feed mainly with organic matter derived from terrestrial plants!

And of course, allochtonous inputs (food items from outside of the ecosystem), like fruits, seeds, insects, and plant parts, are important food sources to many fishes.  Many midwater characins consume fruits and seeds of terrestrial plants, as well as terrestrial insects.

Insects in general are really important to fishes in blackwater ecosystems. In fact, it's been concluded that the the first link in the food web during the flooding of forests is terrestrial arthropods, which provide a highly important primary food for many fishes.

These systems are so intimately tied to the surrounding terrestrial environment. Even the permanent rivers have a strong, very predictable "seasonality", which  provides fruits, seeds, and other terrestrial-originated food resources for the fishes which reside in them. It's long been known by ecologists that rivers with predictable annual floods have a higher richness of fish species tied to this elevated rate of food produced by the surrounding forests.

And of course, fungal growths and bacterial biofilms are also extremely valuable as food sources for life forms at many levels, including fishes. The growth of these organisms is powered by...decomposing leaf litter! 

Sounds familiar, huh?

So, how does a leaf break down? It's a multi-stage process which helps liberate its constituent compounds for use in the overall ecosystem. And one that is vital to the construction of a food web.

The first step in the process is known as leaching, in which nutrients and organic compounds, such as sugars, potassium, and amino acids dissolve into the water and move into the soil.The next phase is a form of fragmentation, in which various organisms, from termites (in the terrestrial forests) to aquatic insects and shrimps (in the flooded forests) physically break down the leaves into smaller pieces. 

As the leaves become more fragmented, they provide more and more surfaces for bacteria and fungi to attach and grow upon, and more feeding opportunities for fishes!

Okay, okay, this is all very cool and hopefully, a bit interesting- but what are the implications for our aquariums? How can we apply lessons from wild aquatic habitats vis a vis food production to our tanks? 

This is one of the most interesting aspects of a botanical-style aquarium: We have the opportunity to create an aquatic microcosm which provides not only unique aesthetics- it provides nutrient processing, and to some degree, a self-generating population of creatures with nutritional value for our fishes, on a more-or-less continuous basis.

Incorporating botanical materials in our aquariums for the purpose of creating the foundation for biological activity is the starting point. Leaves, seed pods, twigs and the like are not only "attachment points" for bacterial biofilms and fungal growths to colonize, they are physical location for the sequestration of the resulting detritus, which serves as a food source for many organisms, including our fishes.

Think about it this way: Every botanical, every leaf, every piece of wood, every substrate material that we utilize in our aquariums is a potential component of food production!

The initial setup of your botanical-style aquarium will rather easily accomplish the task of facilitating the growth of said biofilms and fungal growths. There isn't all that much we have to do as aquarists to facilitate this but to simply add these materials to our tanks, and allow the appearance of these organisms to happen. 

You could add pure cultures of organisms such as Paramecium, Daphnia, species of copepods (like Cyclops), etc. to help "jump start" the process, and to add that "next trophic level" to your burgeoning food web. 

In a perfect world, you'd allow the tank to "run in" for a few weeks, or even months if you could handle it, before adding your fishes- to really let these organisms establish themselves. And regardless of how you allow the "biome" of your tank to establish itself, don't go crazy "editing" the process by fanatically removing every trace of detritus or fragmented botanicals.

"Project 18" was a tank which really pushed this idea to the forefront of my daily practice. Everything from the selection of materials to the way the tank was set up, to the "aquascape" was imagined as a sort of "whole."

Yeah, I said the "A" word...Let's think about the "aquascape" part bit more deeply for just a second...

What IS the purpose of an aquascape in the aquarium...besides aesthetics? Well, it's to provide fishes with a comfortable environment that makes them feel "at home", right?

Exactly...

So when was the last time you really looked into where your fishes live- or should I say, "how they live" - in the habitats from which they come? The information that you can garner from such observations and research is amazing!

One of the key takeaways that you can make is that many freshwater fishes like "structure" in their habitats. Unless you're talking about large, ocean going fishes, or fishes that live in enormous schools, like herring or smelt- fishes like certain types of structure- be it rocks, wood, roots, etc.

Structure provides a lot of things- namely protection, shade, food, and spawning/nesting areas.

And of course, the structure that we are talking about in our aquairums is not just rocks and wood...it's all sorts of botanical materials and leaves that create "microhabitats" in all sorts of places within the aquarium.

We can utilize all of these things to facilitate more natural behaviors from our fishes.

So, yeah-think about how fishes act in Nature.

They tend to be attracted to areas where food supplies are relatively abundant, requiring little expenditure of energy in order to satisfy their nutritional needs. Insects, crustaceans, and yeah- tiny fishes- tend to congregate and live around floating plants, masses of algae, and fallen botanical items (seed pods, leaves, etc.), so it's only natural that our subject fishes would be attracted to these areas...

I mean, who wouldn't want to have easy access to the "buffet line", right?

And with the ability to provide live foods such as small insects (I'm thinking wingless fruit flies and ants)- and to potentially "cultivate" some worms (Bloodworms, for sure) "in situ"- there are lots of compelling possibilities for creating really comfortable, natural-appearing (and functioning) biotope/biotype aquariums for fishes.

Ever the philosopher/ muser of the art of aquaristics, I sometimes fear that the burgeoning interest in biotope aquariums at a contest level will result in the same sort of "diorama effect" we've seen in planted aquarium contests. In other words, just focusing on the "look" (which is cool, don't get me wrong) yet summarily overlooking the reason why the habitat looks the way it does and how fishes have adapted to it...and considering how we can utilize this for their husbandry, spawning, etc.

I'm sure it's unfounded, but the so-called "nature aquarium" movement seems to have, IMHO, completely overlooked the real function of nature, so there is some precedent, unfortunately. I hope that "biotopers", who have a lot of awareness about the habitats they are inspired by, will at least consider this "functional/aesthetic" dynamic that we obsess over when they conceive and execute their work. 

It should go beyond merely creating the "look" of these systems to win a contest, IMHO. Rather, we should also focus on the structural/functional aspects of these environments to create long-term benefits for the fishes we keep in them. That's a real "biotope aquarium" in my book.

Leaves, detritus, submerged terrestrial plants- all have their place in an aquarium designed to mimic these unique aquatic habitats.  You can and should be able to manage nutrients and the bioload input released into our closed systems by these materials, as we've discussed (and executed/demostrated) here for years.  The fear about "detritus" and such "crashing tanks" is largely overstated, IMHO- especially with competent aquarium husbandry and proper outfitting of a tank with good filtration and nutrient control/export systems in place.

If you're up to the challenge of attempting to replicate the look of some natural habitat- you should be a competent enough aquarist to be able to responsibly manage the system over the long term, as well.

Ouch, right?  Hey, that's reality. Sorry to be so frank. Enough of the "shallow mimicry" B.S. that has dominated the aquascaping/contest world for too long, IMHO. You want to influence/educate people and inspire them? Want to really advance the hobby and art/science of aquarium keeping? Then execute a tank which can be managed over the long haul. Crack the code. Figure out the technique. Look to Nature and "back engineer" it.

These things can be done. 

There are many aspects of wild habitats that we choose to replicate, which we can turn into "functionally aesthetic" aquarium systems. Let's not forget the trees themselves- in their submerged and even fallen state! These are more than just "hardscape" to those of us who are into the functional aesthetic aspects of our aquariums.

I hope that you have your own "Project 18"- an aquarium which served as an "unlock" for the future of your botanical method work. I hope that you find your unique way in the hobby, and enjoy every second of it!

Stay bold. Stay creative. Stay observant. Stay thoughtful...

And Stay Wet.

Scott Fellman

Tannin Aquatics