July 21, 2021

The Essence...

The expectations that we have about our botanical-style aquariums after years of playing with this stuff are pretty well-known by now. We know that botanical materials are dynamic, and simply don't last indefinitely when submerged. They are not permanent additions to our aquariums.

Yet, there are still many things about using botanical materials in our tanks that we don't all seem to have grasped. Like, the idea that we are adding these materials not only to influence the aquatic environment in our aquariums, but to provide food and sustenance for a wide variety of organisms, not just our fishes. The fundamental essence of the botanical-style aquarium is that the use of these materials provide the foundation of an ecosystem.

The essence.

Just like they are in Nature.

And the primary process which drives this closed ecosystem is decomposition.

Decomposition of leaves and botanicals not only imparts the substances contained within them (lignin, organic acids, and tannins, just to name a few) to the water- it serves to nourish bacteria, fungi, and other microorganisms and crustaceans, facilitating basic "food web" within the botanical-style aquarium- if we allow it to!

Decomposition of plant matter-leaves and botanicals- occurs in several stages.

It starts with leaching -soluble carbon compounds are liberated during this process. Another early process is physical breakup or fragmentation of the plant material into smaller pieces, which have greater surface area for colonization by microbes.

And of course, the ultimate "state" to which leaves and other botanical materials "evolve" to is our old friend...detritus.

And of course, that very word- as we've mentioned many times here- has frightened and motivated many hobbyists over the years into removing as much of the stuff as possible from their aquariums whenever and wherever it appears.

Siphoning detritus is a sort of "thing" that we are asked about near constantly. This makes perfect sense, of course, because our aquariums- by virtue of the materials they utilize- produce substantial amounts of this stuff.

Now, the idea of "detritus" takes on different meanings in our botanical-style aquariums...Our "aquarium definition" of "detritus" is typically agreed to be dead particulate matter, including fecal material, dead organisms, mucous, etc.

And bacteria and other microorganisms will colonize this stuff and decompose/remineralize it, essentially "completing" the cycle.

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-and the processes which form them- are beautiful.

And the realization that this is not "a style of aquascaping" is really important.

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.

An important part of this little microcosm are fungi.

Yeah, you heard me. Fungi.

Fungi reproduce by releasing tiny spores that then germinate on new and hospitable surfaces (ie, pretty much anywhere they damn well please!). These aquatic fungi are involved in the decay of wood and leafy material. And of course, when you submerge terrestrial materials in water, growths of fungi tend to arise.

Anyone who's ever "cured" a piece of wood of almost any type for your aquarium can attest to this!

Fungi tend to colonize wood because it offers them a lot of surface area to thrive and live out their life cycle. And cellulose, hemicellulose, and lignin- the major components of wood and botanical materials- are degraded by fungi which posses enzymes that can digest these materials! Fungi are regarded by biologists to be the dominant organisms associated with decaying leaves in streams, so this gives you some idea as to why we see them in our aquariums, right?

And of course, fishes and invertebrates which live amongst and feed directly upon the fungi and decomposing leaves and botanicals contribute to the breakdown of these materials as well!

Aquatic fungi can break down the leaf matrix and make the energy available to feeding animals in these habitats. The fungi known as aquatic hyphomycetes produce enzymes which cause leaf maceration, and in as little as 2 to 3 weeks, as much as 15% of the decomposing leaf biomass in many aquatic habitats is processed by fungi, according to one study that I found.

The process is important in wild habitats, just as it is in the aquarium.

In experiments carried out by aquatic ecologists in tropical forests in Venezuela, decomposition rates were really fast, with 50% of leaf mass loss in streams occurring in less than 10 days!

The ultimate result is the transformation of what ecologists call "coarse particulate organic matter" (C.P.O.M.) into "fine particulate organic matter" (F.P.O.M.), which may constitute an important food source for other organisms we call “deposit feeders” (aquatic animals that feed on small pieces of organic matter that have drifted down through the water and settled on the substrate) and “filter feeders” (animals that feed by straining suspended organic matter and small food particles from water), as well as worms, planaria, and insects.

By studying and encouraging the growth of this diversity of organisms, and creating a multi-faceted microcosm of life in our tanks, I believe that we are contributing to an exciting progression of the art and science of aquarium keeping!

And I have a theory that many of these things- these processes, and the life forms which create them- that we as hobbyists often try to "edit", "polish", or skip altogether, are often the most important and foundational aspects of botanical-style aquarium keeping!

It's why we literally pound it into your head over and over here that you not only shouldn't try to circumvent these processes and occurrences- you should embrace them and attempt to understand exactly what they mean for the fishes that we keep. They're a key part of the functionality.

Starting your aquarium by "populating" it with botanical materials that will slowly decompose is absolutely analogous to what happens in wild aquatic habitats.

In Nature, terrestrial materials covered by water are the basis for almost every aquatic ecosystem. The processes of decomposition and colonization- and utilization- of these materials by an enormous variety of organisms- is truly what "powers" these ecosystems.

It works exactly the same in an aquarium...If we let Nature do her work without excessive intervention.

Further, I'm thinking that we should do less and less preparation of certain botanical materials-specifically, wood- to encourage a slower breakdown and colonization by beneficial bacteria and fungal growths. The "rap" on wood has always been that it gives off a lot of tint-producing tannins, much to the collective freak-out of non-botanical-style aquarium fans. However, to us, all those extra tannins are not much of an issue, right? Weight down the wood, and let it "cure" in situ before adding your fishes!

And then there is the whole concept of getting fishes into the tank as quickly as possible.

Like, why?

We should slow our roll.

I've written and spoken about this idea before, as no doubt many of you have: "Pre-colonizing" your aquarium with beneficial life forms BEFORE you ever think of adding fishes to it, and establishing a "functional" hardscape environment at the same time. A way to sort of get the system "broken in", with a functioning little food web and nutrient export processes in place. A chance for the life forms that would otherwise likely fall prey to the fishes to get a "foothold" and multiply, to help create a sustainable population of self-generating prey items for your fishes.

You set up your aquarium, complete with some botanicals, leaves, and wood, and add cultures of animals like Paramecium, rotifers, Euglenids, Gammarus, Daphnia, etc., and let them go to work on the decomposing leaves, etc. The hard part is....waiting. Yeah, waiting to add ANY fishes for at least a couple of months or so, to really give the animals present a chance to settle in and reproduce. Trust me, it's not as easy as you might think. You've spent all of this money on a cool idea for an aquarium; you're ready to go...and then you're looking at a dark tank with the occasional Daphnia sighting.

Wow. Crazy. Okay, I hear the groaning already...

I'm really having trouble grasping exactly what the problem is with this approach- other than the obscene amount of patience we have to deploy as hobbyists waiting for our tanks to settle in and be "just right" for fishes.

Remember, we're not just about an aesthetic here! Where is the food web? Where is the "functionality" of the system? These things form over time, but from day one, you have a box filled with botanicals, sand. leaves, and wood. We can do better in this regard, right?

How come we haven't?

Is it because we've always been told NOT to start aquariums this way? Maybe? I mean, the aquariums that we play with in own our world are not exactly "conventional", right?

So why should the way we establish them be?

Now, going more slowly doesn't have to be this tortuous, painful process.

And of course, there are a few things you could do to sort of "expedite" the "established" look of a botanical-style tank, but they're really just sort of "hacks" (ugh I hate that word!)- and are no substitutes for just letting a tank evolve over time naturally.

"Well, what are they, Fellman?"

So you could use some botanicals and partially decomposed leaf litter, substrate, and even water from an established botanical-style tank to give you a bit more of an "evolved" vibe and definitely some microbial populations and therefore, some function.

And, if doing this for purely "functional" reasons as opposed to just trying to "hack" the "look"- I can actually see tremendous merit to this idea. Hell, adding sand or gravel from an established tank to "jump-start" a new one has been standard practice in marine aquariums for decades, and in freshwater as well.

Doing this with botanical materials- rich with detritus, biofilms, fungal growth, and beneficial bacteria- is simply the botanical-style version of this time-honored process, right? And it makes perfect sense.

Yet, there is no substitute for patience and the passage of time.

Looking back on some of my favorite tanks that I've executed in the past few years, it becomes increasingly obvious to all that these systems really don't hit that "look and feel" that we expect until long after they have evolved naturally...however long that is.

Stuff needs to acquire a "patina" of biofilm, a "stain" from the tannins, and decomposition of botanical materials needs to really begin before one of these systems turns "functional" as well.

I mean, every new botanical-style tank looks cool from day one...A lot of people love the clean and fresh-looking leaves, and seed pods that are squeaky clean. But the long-established systems are the ones that stand out.

The thoughts I just shared about "kick-starting"are metaphorical band aids, props- helpful quick starts…”hacks”, if you will. But they are not the whole key to establishing a successful long-term-viable aquarium. Ultimately, Nature, the ultimate "editor"- has to “approve” and work with any of the “boosts” we offer.

Nature dictates the pace.

The reality is that the journey to the so-called “finished product” is really every bit as interesting as the finished product itself!

It’s where the magic lies. The process. The journey. The time. The evolution. The patience.

You could even run your tank "dry" in the "Urban Igapo" style for some period of time before filling. If you're uber patient.

All of these processes rather elegantly (or crudely, I suppose one could say) mimic some of the things that happen in Nature as the "rainy season" or "dry season", as the case may be- progress. You could conceivably start your tank in the igapo "dry season"- or vice versa- and progress it from there!

Each one of these manipulations has multiple implications, benefits, consequences, influences, and lessons to be learned. Any one of them can be a key factor in the successful husbandry of a number of fishes...we just need to try!

They all require a little creativity, vision, and a hell of a lot of patience to allow some space for Nature "do Her thing."

That's the essence of a botanical-style aquairum.

Stay patient. Stay diligent. Stay methodical. Stay curious. Stay unique...

And Stay Wet.

Scott Fellman

Tannin Aquatics