"Passive management" and the evolving aquarium...

Have you ever considered the "lifetime" of an aquarium?  I mean, does an aquarium HAVE a lifetime? Or will it just go indefinitely if we let it?

What does that even mean, in aquarium terms?

I like to think about aquariums as I do a garden.

Yeah, aquariums are very much like terrestrial gardens.

They have 'ebb and flow" (literally, in some cases!), growth, challenges, and dieback..they have setbacks- and rebounds. I'll bet that if you tracked what happened in a "community aquarium" over the course of say, two years, what you end up with after two years may be significantly different than what you started with. 

In a reef aquarium, where corals are competing for light, nutrients, and space, this type of "evolutionary" change takes place. It's near constant, and it can be quite profound.

Oh, sure, some of the changes that occur during the "life" of an aquarium are human-imposed, such as equipment modifications/replacements, aquascaping "edits", fish and plant additions, etc. However, if you look carefully (as I'm sure that you do), as many changes can be attributed to the cycle of life which occurs in your little microcosm as to human "intervention" of the aquarium environment. 

Things like the growth and/or "dieback" of plants, the proliferation of algae, the gradual decay of wood and aquatic botanicals, social hierarchies among inhabitants, the "patina" of biofilm/algae, however subtle, that makes fresh aquarium substrate "matte out" over time, looking more natural, more subtle...more full of life.

What the Japanese call "wabi-sabi"- the transient nature of things- is both beautiful and inevitable.

And change doesn't happen uniformly, either.

I remember from my experience growing corals commercially, that on any given day, some of the many thousands of specimens we had growing in our facility would be struggling. Some would be absolutely cranking!

Others would be just sort of "there."

And it would change constantly. It was a great demonstration for me of what aquatic husbandry is all about. You need to observe, tweak, and sometimes, simply get out of the way.

The science is one thing.

You learn "best practices" and protocols very quickly, and adhere to them. The "art" of being an aquarist- the really tricky part of this game- is how we choose to manage this multifaceted microcosm, with all of its "moving parts" and subtle complexities.

We can let things decline. Or, we can take charge and attempt to stave off the inevitable. Botanical-style aquariums offer numerous opportunities for making changes- or not.

How we as humans choose to accept this progression and change is purely based on our own tastes.

The reality is that these things will continue despite any interventions we perform on our tanks. We can "resist" them, performing "maintenance" takes on our tanks, like trimming plants, fragging corals, scraping algae, stirring the top layers of substrate, etc.- but these are merely serving to counteract or stave off the inevitable changes that occur in an aquarium as it establishes itself, begins to thrive, and gradually declines.

Of course, in many cases, the "decline" is so gradual, so subtle, that the outsider hardly notices.  In the case fo a botanical-style aquarium, with its abundance of seed pods, leaves, and other materials, you'd be hard-pressed to really call it a "decline." It's more like an evolution, really.

You, the aquarist, ever keen on anything that occurs in your tank, will notice- and often perform subtle (or not-so-subtle) interventions to counteract this process, lest it descend into some sort of chaos, right? 

Yet, isn't "chaos" sort of a human-ascribed thing? I mean, we're talking about changes in the aquatic habitat which evolve the look and perhaps the biological "operating system" of the aquarium. This is absolutely analogous to what happens in natural aquatic systems.

Stuff breaks down, and different types of organisms flourish and reproduce as a result. Nothing goes to waste in Nature...and that includes the "nature" which is found in our aquariums, too..If we allow it to happen.

It's entirely possible, in my humble opinion, that we, as aquarists actually sabotage the essential natural processes which help our tanks run when we attempt to "intervene" through excessive maintenance.

Perhaps a hands-off approach- "passive management", if you will- is not always a bad thing.

I sometimes wonder what our aquariums would evolve into over the course of a couple of years if we merely performed basic maintenance tasks, such as water changes, equipment maintenance, feeding, scraping the viewing panels, etc., and did little else. No animal replacement. No trimming of plants, fragging of corals, or removal of fish fry. No rearranging of the aquascape. 

What would you end up with?

Of course, the answer depends upon what the "end point" is. For that matter- does there have to be one?

It seems that in recent years, I've executed more aquariums in a shorter period of time than ever in my aquatic career. Unusual for me, because, as you might imagine- I'm kind of a "leave the tank be" kind-of-guy.

One of the ideas we play with quite a bit is hardly "radical" in it's departure- you've likely done a version of this hundreds of times during your aquarium hobby career: It's the idea of keeping your aquarium more-or-less "intact" while moving on to a new iteration.

In other words, you're kind of over your Southeast Asian Cryptocoryne biotope, and ready to head West to South America. So, rather than tearing up the entire tank, removing all of the plants, the hardscape, the leaves and botanicals, and the substrate, you opt to remove say, only the plants and the driftwood/rocks from the tank; exchange a good quantity of the water.

Woooah! Crazy! Fellman, you fucking rebel...

I know. I know. This isn't exactly earth-shattering. 

On the other hand, in the world of the botanical-style aquarium, the idea of leaving the substrate and leaf litter/botanical "bed" intact as you "remodel" isn't exactly a crazy one. And conceptually, it's sort of replicates what occurs in Nature, doesn't it?

Yeah, think about this for just a second.

As we almost constantly discuss here, habitats like flooded forests, meadows, vernal pools, igarape, and swollen streams tend to engulf terrestrial habitats, or go through phases where they are terrestrial habitats for a good part of the year.

In these wild habitats, the leaves, branches, soils, and other botanical materials remain in place, or are added to by dynamic, seasonal processes. For the most part, the soil, branches, and a fair amount of the more "durable" seed pods and such remain present during both phases.

The formerly terrestrial physical environment is now transformed into an earthy, twisted, incredibly rich aquatic habitat, which fishes have evolved over eons to live in and utilize for food, protection, and complex, protected spawning areas. 

All of the botanical material-shrubs, grasses, fallen leaves, branches, seed pods, and such, is suddenly submerged; often, currents re-distribute the leaves and seed pods and branches into little pockets and "stands", affecting the (now underwater) "topography" of the landscape.

Leaves begin to accumulate. Detritus settles.

Soils dissolve their chemical constituents- tannins, and humic acids- into the water, enriching it. Fungi and micororganisms begin to feed on and break down the materials. Biofilms form, crustaceans multiply rapidly.  Fishes are able to find new food sources; new hiding places..new areas to spawn.

Life flourishes.

Nature doesn't "edit." She evolves.

Could you resist "editing" your aquarium for a period of time? Would you want to? Is rearranging stuff and re-working things as much part of the hobby as just looking into the tank and enjoying it?

And if you went completely "hands-off" with your tank, what would happen?

No one said the hobby is easy, but it’s not difficult, either- as long as you have a basic understanding of the environmental processes and conditions within your aquarium. And the idea of leaving essential biological components of your aquarium more-or-less "intact" for an indefinite period of time is really compelling.

What would happen?

Would anarchy reign, or would a different sort of system ultimately evolve? Would it succeed on some level that you wouldn't have considered previously? What would come to dominate, and what would fade away?

How would Nature work with what you gave her in your little glass or acrylic world called "an aquarium?"

How would "passive management" affect the dynamics of this microcosm?

Fun questions to ponder. Perhaps.

Stay  curious. Stay thoughtful. Stay engaged. Stay full of wonder. Stay passive?

And Stay Wet.


Scott Fellman

Tannin Aquatics.



Scott Fellman
Scott Fellman


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