Over the years, I know that I've learned a few things about managing my aquariums over the long term. The most interesting lesson to me is that you can always make changes, evolutions, and iterations...without completely breaking down the tank as you do them.
You can make seemingly dramatic changes to your aquariums, and yet still leave considerable parts of them intact and functional.
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? Materials accumulate on top of other materials, facilitating new biological growth, continued foraging for resident fishes, and a more or less uninterrupted ecology.
Yeah, think about this for just a second.
As we almost constantly discuss, habitats like flooded forests (Igapo and Varzea), meadows, vernal pools, igarape, and swollen streams tend to encompass 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.
When you remove much of the hardscape, plants, etc. from the aquarium as you "evolve" it to something else, yet leave the substrate, some of the hardscape, leaves, etc. intact, you're essentially mimicking this process in a most realistic way.
Sure, a "makeover" of an aquarium can be a seriously disruptive event (for both YOU and your fishes!).
On the other hand, if you take the mindset that this is a "transformation" of sorts, and act accordingly, it becomes more of an evolutionary process.
This is something I've done for many years- like a lot of you have, and it not only makes your life a bit easier- it can create pretty good outcomes for the fishes we keep.
The "Urban Igapo" idea that I've been touting for a good part of the year is a very deliberate execution of this iterative process, and it's taught me quite a bit about how these habitats function in Nature, and what kinds of benefits they bring to the aquarium.
We've talked about the idea of "flooding" an aquarium setup designed to replicate an Amazonian forest before. You know, sort of attempting to simulate some of the processes which happen seasonally in Nature. With the technology, materials, and information available to us today, the capability of creating a true "year-round" habitat simulation in the confines of an aquarium/vivarium setup has never been more attainable.
The time to play with this concept is now!
We've been playing with the idea for a long time, and spent a long time formulating our "NatureBase" soils, which attempt to replicate some of the attributes of those found in these habitats during the "dry" season. When flooded, you get an effect that's similar to what happens in the igapo.
Sure, the water gets cloudy for a bit. The water is tinted, turbid, and sediment-laden. Eventually, it settles out. If you planted grasses and plants which are able to tolerate submersion for some period off their life cycle, they'll "hang on" for a while- until the waters recede.
Just like in Nature.
And you can go through multiple "wet and dry seasonal cycles" with the same substrate and perhaps only a slight addition of materials to replenish those which have broken down, but the result is a "continuous aquarium"- one which can stay more-or-less intact over a long period of time and iterations.
This can work in all types of aquariums- large and small.
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. You can be fairly aggressive at "remodeling" your tank without fear of the tank "cycling" again, in my experience.
And the idea of leaving essential biological components of your aquarium more-or-less "intact" for an indefinite period of time is really compelling.
Of course, an aquarium which utilizes botanicals as a good part of its hardscape follows a set of phases, too. And I've found that once a botanical-style aquarium (blackwater or brackish) hits that sort of "stable mode", it's just that- stable. You won't see wildly fluctuating pH leaves, nitrates, phosphates, etc. To a certain degree, the aquarium has achieved some sort of "biological equilibrium."
Of course, the thing that's unique about the botanical-style approach is that we tend to accept the idea of decomposing materials accumulating in our systems. We understand that they act, to a certain extent, as "fuel" for the micro and macrofauna which reside in the aquarium. The idea of leaving this material in place over the long-term is a crucial component of this approach, IMHO.
As we've discussed repeatedly, just like in Nature, they'll also form the basis of a complex "food chain", which includes bacterial biofilms, fungi, and minute crustaceans. Each one of these life forms supporting, to some extent, those above...including our fishes.
So, when you're contemplating and executing your "evolutions" I have long believed that if you decide to let the botanicals remain in your aquarium to break down and decompose completely, you shouldn't change course by suddenly removing the material all at once...Particularly if you're going to a new version of an existing aquarium.
Well, I think my theory is steeped in the mindset that you've created a little ecosystem, and if you start removing a significant source of someone's food (or for that matter, their home!), there is bound to be a net loss of biota...and this could lead to a disruption of the very biological processes that we aim to foster.
Okay, it's a theory...But I think I might be on to something, maybe? So, like here is my theory in more detail:
Simply look at the botanical-style aquarium (like any aquarium, of course) as a little "microcosm", with processes and life forms dependent upon each other for food, shelter, and other aspects of their existence. And, I really believe that the environment of this type of aquarium, because it relies on botanical materials (leaves, seed pods, etc.), is more signficantly influenced by the amount and composition of said material to "operate" successfully over time.
Just like in natural aquatic ecosystems...
The botanical materials are a real "base" for the little microcosm we create.
And of course, by virtue of the fact that they contain other compounds, like tannins, humic substances, lignin, etc., they also serve to influence the water chemistry of the aquarium, the extent to which is dictated by a number of other things, including the "starting point" of the source water used to fill the tank.
So, in short- I think the presence of botanicals in our aquariums is multi-faceted, highly influential, and of extreme importance for the stability, ecological balance, and efficiency of the tank.
Okay, I might just be torturing this simple idea to death- I admit this point that I'm probably not adding much more to the "recipe" here; likely simply being redundant and even a bit vague- and "multi-faceted" sounds liek a poor way of saying, "They do a lot!"...However, I think we need to think about how interesting this simple practice is.
And yeah, I'll concede that we probably don't have every answer on the processes which govern this stuff. In fact, we barely have any, really...
The most common question I get when it comes to taking out a fair amount of this material and then "continuing" the tank is, "Will it cycle again?"
And the answer is...It could.
On the other hand, here is my personal experience: Remember, I keep a sort of diary of most of my aquarium work. I have for over three decades (gulp...). Just random scanning my "diary", I see that I have executed this practice dozens of times in all types of aquariums, ranging from simple planted aquariums to hardscape-only tanks, to botanical-style, blackwater and brackish aquariums, to reef tanks.
Not once- as in never- have I personally experienced any increase in ammonia and nitrite, indicative of a new "cycle."
Now, this doesn't mean that I guarantee a perfect, "cycle-free" process for you. On the other hand, by leaving the bulk of the substrate material intact, and continuing to provide "fuel" for the extant biotia by leaving in and adding to the botanicals present in the aquarium, this is entirely possible, as my experiences have shown me.
Some of you have asked why I'm so confident in my ability to iterate tank in this rather aggressive fashion. No, it's not because I'm some brilliant pioneer who knows something others don't.
It's because I-like many of you- have adopted a special mindset.
A mindset- and consistent husbandry practices that assure success with this process.
I am a fanatical observer of my aquariums, particularly the botanical-style ones I run (oh, all of them...), and I do the same things over and over and over again; specifically, weekly small water exchanges. I don't overcrowd my tanks. I don't add tons of fishes at one time. I don't overfeed my fishes. I don't add a large batch of botanicals at one time to "remodeled" or existing aquariums. I'm annoyingly patient. I don't freak out over things taking a while.
I embrace "detritus" ( at least the kind that is caused by mineralization of botanical materials) as "fuel" for the biological "operating system"- not as something to be afraid of.
And, like many of you, I don't see a need to rush to some version of "finished."
Personally, I don't think that botanical-style aquariums are ever "finished." They simply continue to evolve over extended periods of time, just like the wild habitats that we attempt to replicate in our tanks do...
And the botanicals in the aquarium? Well. they'll keep breaking down, "enriching" the aquarium habitat. Imparting humic substances, lignin, etc. Compounds which have a material impact on the ecology, biology, and chemistry of the aquarium.
Understand and facilitate these natural processes into your aquariums. Keep that in mind when you "iterate" an aquarium.
If you're months into a tank, and simple don't like the look or performance or whatever- you can easily change it. It's a lot like catching a continuously-running commuter train or subway line, right? There's always an opportunity to go somewhere new. You just have to jump on.
Part of the beauty of the botanical-style aquarium is that you can sort of "pick it up where you are" and "ride it" out for a while, or change the "routing" as you desire! Started your tank as an Amazonian habitat but you're suddenly enamored with a more "Asian" look?
Keep the "operating system" intact, but change out some elements. Don't feel compelled to "siphon out all of the detritus" or whatever the B.S. that you hear regurgitated when people talk about tank makeovers. Unless you're tearing apart the tank because it's a smelly, stinky, mismanaged, toxic pile of shit that's killing your fishes, keep the biological "fuel" intact for your new iteration! (and vow to take better care of your tank this time!)
Super easy, right?
It is. If you let it be that way.
Evolution in our aquariums is not only fun to watch, it's a lot of fun to manage as well. And it's even more fun to have the option to do either!
Our aquariums can operate continuously for indefinite periods of time if we allow them to do so. It's a compelling, fascinating idea and process.