Continuity, renewal, stability...and evolution...

As I've loudly and repeatedly announced lately, I've embarked on some "remodels" of some of the aquariums in our office, and it's been a most interesting experience- as it always is. I've taken a slightly different approach to these "makeovers" over time. Specifically, one of the things I've done in recent years is to keep the substrate layers from the existing tanks and "build on them." 

In other words, I'm taking advantage of the well-established substrate layers, complete with their sediments, decomposing leaves and bits of botanicals, and simply building upon them with some additional substrate and leaves. I've done this many times over the years- it's hardly a "game-changing" practice, but it's something not everyone recommends or does.

I believe that preserving and building upon an existing substrate layer provides not only some biological stability (ie; the nitrogen cycle), but it has the added benefit of maintaining some of the ecological diversity and richness created by the beneficial fuana and the materials present within the substrate.  I know many 'hobby old timers" might question the safety- or the merits-of this practice, mentioning things like "disturbing" the bacterial activity" or "releasing toxic gasses", etc. I simply have never experienced any issues of this nature from this practice. Well maintained systems generally are robust and capable of evolving from such disturbances. 

I see way more benefits to this practice than I do any potential issues.

Since I tend to manage the water quality of my aquariums well, I have never had any issues, such as ammonia or nitrite spikes, by doing this- in fresh or saltwater systems. It's a way of maintaining stability- even in an arguably disruptive and destabilizing time!

This idea of "perpetual substrate"- keeping the same substrate layer "going" in successive aquarium iterations- is just one of those things we can do to replicate Nature in an additional way. Huh? Well, think about it for just a second. In Nature, the substrate layer in rivers, streams, and yeah, flooded forests and pools tends to not completely wash away during wet/dry or seasonal cycles.

Oh sure, some of the material comprising the substrate layer may get carried away by currents or other weather dynamics, but for the most part, a good percentage of the material- and the life forms within it- remains.

So, by preserving the substrate and "refreshing" it a bit with some new materials (ie; sand, sediment, gravel, leaves, and botanicals), you're essentially mimicking some aspects of the way Nature functions in these wild habitats. And, from an aquarium management perspective, consider the substrate layer a living organism (or "collective" of living organisms, as it were), and you're sure to look at things a bit differently next time you re-do a tank!

Of course, perpetuating the substrate is almost like persuing "eternal youth"- it's not entirely possible to achieve, but you can embrace the idea of renewal and continuity within your aquarium.

Things change in Nature, but other things are also preserved. Nothing goes to waste.

And yet, one concept about botanical-style aquariums that I can't seem to bring up enough is the idea that many of the habitats we like to represent in our tanks- and the materials which we utilize to 'scape them, are ephemeral. In other words, they are not "permanent" features, in the same way a rock or a piece of wood is-instead, breaking down and decomposing following long-term submersion.

I find the ephemeral quite alluring. 

Leaves, of course, are the ultimate statement of Nature's ephemeral character. Things always change. Nothing lasts forever- at least, not in its original form. Leaves begin to break down and impart organic materials, ranging from lignins to tannins to humic substances- even sugars- into the water.

One interesting observation I’ve made over the years concerning adding leaves to the aquarium and letting them decay: Dead, dried leaves such as those we favor don’t have nearly the impact on water quality, in terms of nitrate, as fresh leaves would (and yeah, I've played with both...). I’ve routinely seen undetectable nitrate levels in aquariums loaded with botanicals. This is largely because dead, dried leaves have depleted the vast majority of stored sugars and other compounds which lead to the production of nitrogenous substances in the confines of the aquarium.

Hence, leaving leaves in to fully decay likely reaches a point when the detritus, which results is essentially inert, consisting of the "skeletonized" sections of leaf tissue which can decay no further. Dead leaves contain largely inert forms of polysaccharides, and are rich in structures like lignin and cellulose. Just keeping overall water quality consistently high is a great practice.

Oh, and doing regular water changes can’t hurt...😆

And, of course, in the aquarium, much like in the natural habitat, the layer of decomposing leaves and botanical matter, colonized by so many organisms, ranging from bacteria to macro invertebrates and insects, is a prime spot for fishes! The most common fishes associated with leaf litter in the wild are species of characins, catfishes and electric knife fishes, followed by our buddies the Cichlids (particularly ApistogrammaCrenicichla,  and Mesonauta species)!

Some species of Rivulus killies are also commonly associated with leaf litter zones, even though they are primarily top-dwelling fishes.  Leaf litter beds are so important for fishes, as they become a refuge for fish providing shelter and food from associated invertebrates.

And of course, the eternal question: How often do you need to replace your leaves?

Well, it's another great question for which there is no "rule" involved. The reality is that you can simply add new leaves on a regular basis, so you'll always be making up for the ones that have decomposed. Some hobbyists like to remove the decomposed leaves, preferring a more "pristine" look. It boils down to aesthetics, really.

Of course, there are those functional and ecological aspects, too...right?

And besides leaves and seed pods, there is that other "stuff" that we all love..Branches, stems...twigs.

Those of us who obsessively study images of the wild tropical habitats we love so much can't help but note that many of the bodies of water which we model our aquariums after are replete with tree branches and stems. Since many of these habitats are ephemeral in nature, they are only filled up with water part of the year.

The remainder of the time, they're essentially dry forest floors.

And what accumulates on dry forest floors?

Branches, stems, and other materials from trees and shrubs!

When the waters return, these formerly terrestrial materials become an integral part of the (now) aquatic environment. This is a really, really important thing to think of when we aquascape or contemplate who we will use botanical materials like the aforementioned stems and branches. They impact both function and aesthetics of an aquarium...Yes, what we call "functional aesthetics" rears its head again!

And, from the perspective of the aquascaper, this dynamic can be either stimulating or challenging...or both, depending upon how you look at it. There is no real rhyme or reason as to which materials orient themselves the way they do. I mean, branches fall off the trees- a process initiated by either rain or wind- and just land "wherever." Which means that we as hobbyists would be perfectly okay just sort of "tossing materials in the tank" and walking away!  I'm serious. Now, I know this is actually aquascaping heresy- Not one serious 'scaper would ever do that...right?

I'm not so sure why they wouldn't. 

I mean, what's wrong with sort of randomly scattering stems, twigs, and branches in your aquascape? It's a near-perfect replication of what happens in Nature! Now, I realize that a glass or acrylic box of water is NOT nature, and there are things like "scale" and "ratio" and all of that shit that hardcore 'scaping snobs will bash you over the head with...

But Nature doesn't give a f--k about some competition aquascaper's "rules"- and Nature as it exists is pretty damn inspiring, right? There is a beauty in the "brutal reality" of sheer randomness. I mean, sure, the position of stones in an "Iwagumi" is beautiful...but it's hardly what I'd describe as "natural."

Nature is...well...Natural. She's the bomb!

Which begs the question: Who really cares? Do what you like! I I get it. Yet, I still think that we could do a lot worse than literally dropping materials into our tanks (taking into account their size of course) and admiring the randomness of it all.

Look to Nature. And be bold.

Think about maintaining the continuity of an ecosystem and perpetuating biological activity and "structural" randomness.

The "mental stretches" that we talk about incessantly here are still occurring for me, years into this game. With each pic I see of the natural habitats we want to emulate, and every beautiful aquarium that I see come to life from our community, it's inspiring, interesting, and engaging. I'm seeing and experiencing new things, coming up with new ideas, and trying to understand and embrace the processes and aesthetics in a whole new light.

I am happy to see many of you doing the same. Evolving.

What do you have up next?

Sure, embracing some different ideas on the management of aquariums and the aesthetics themselves can seem a bit- well, intimidating at first, but if you force yourself beyond just the basic hobby-oriented mindset out there on these topics, there is a whole world of stuff you can experience and learn about!

And the information you can gain from this process just might have an amazing impact on your aquarium practice; that might just lead to some remarkable breakthroughs that will forever change the hobby!

That's the beauty of continuity, renewal...and stability- all working together.

Stay observant. Stay curious. Stay creative. Stay open-minded...

And Stay Wet.


Scott Fellman

Tannin Aquatics 


Scott Fellman
Scott Fellman


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