The "self-feeding aquarium?" A grand experiment, or a form of benign neglect?

Like most of you, I'm a borderline obsessive aquarist...

Like, I constantly observe, test, or tweak each and every tank, every day. That being said, I have learned over the years that a well thought-out aquarium doesn't need endless doting attention on a non-stop basis.

In fact, because of a busy travel schedule, "company building", and just life in general over the last few years, I even might have missed a water exchange or feeding or two..or three...or...

Yeah, I'm not proud of it- but I won't deny it, either.

In my world, missing water exchanges and feedings and such were, for many years, a sort of "scarlet letter" that you ended up wearing for all to see (well, even if no one else knew...you just felt, I dunno...guilty!).

Now, curiously, I always seemed to havereefing friends who were obsessed with- even proud of- their "ability" to run a "successful" system without water exchanges and such. Maybe rebellious types are somehow attracted to me or something? They'd actually use a sort of "reverse mentality", in which you'd hear them proudly brag about stuff like, "I never run a protein skimmer on my reef." Or, "I haven't done a water change in like a year!"  I mean, that was stuff that would make my head explode... I was like, "If you're gonna be a loser aquarist- don't brag about it!"

I take a dim view of some stuff (shocker, I know...)!

Successful tanks require effort and care.

Yeah, I was/am all about continuous, regular maintenance and dedicated husbandry practices-particularly water exchanges, for which there is simply no substitute for, or no valid reason NOT to execute, IMHO. However, there is one "basic" aspect of aquarium keeping that I have always employed a bit of an "intentional avoidance" of:

Feeding.

"WTF, Fellman. Skip a goddam water change...But feeding? Really?"

Yes. Really.

But before you totally trash me for being hypocritical or even lazy, attempting to brazenly flaunt convention, or simply being guilty of a form of "benign neglect"- hear me out. It's not really about being lazy. It's an intentional thing. I plan for it. In fact, you do too, even though you may not think about it.

And it might be a "sort of" deliberate attempt to flaunt convention...in a nice way, of course.

However, this "practice" is part of a larger thesis which I have about botanical-style aquariums and their management, operation, and benefits:

Of all of the things we do in our blackwater/botanical-style aquariums, one of the few "basic practices" that I think we can actually allow Nature to do some of the work on is to provide some sustenance for our fishes.

Think about it: We load up our systems with large quantities of leaves and botanicals, which serve as direct food for some species, such as shrimp, and perhaps Barbs and Loaches.

These materials famously recruit biofilm and fungal growths, which we have discussed ad nasueum here over the years. These are nutritious, natural food sources for most fishes and invertebrates. And of course, there are the associated microorganisms which feed on the decomposing botanicals and leaves and their resulting detritus.

Having some decomposing leaves, botanicals, and detritus helps foster supplemental food sources. 

Now, we have briefly talked about how decomposing leaf litter does support population of "infusoria"- a collective term used to describe minute aquatic creatures such as ciliates, euglenoids, protozoa, unicellular algae and small invertebrates that exist in freshwater ecosystems.

Yet, there is much to explore on this topic. It's no secret, or surprise- to most aquarists who've played with botanicals, that a tank with a healthy leaf litter component is a pretty good place for the rearing of fry of species associated with blackwater environments!

It's been observed by many aquarists, particularly those who breed loricariids, that the fry have significantly higher survival rates when reared in systems with leaves present. This is significant...I'm sure some success from this could be attributed to the population of infusoria, etc. present within the system as the leaves break down.

Biofilms, as we've discussed many times before, contain a complex mix of sugars, bacteria, and other materials, all of which are relatively nutritious for animals which feed on them.

It therefore would make a lot of sense that a botanical-influenced aquarium with a respectable growth of biofilm would be a great place to rear fry! Maybe not the most attractive place, from an aesthetic standpoint- but a system where the little guys are essentially "knee deep" in supplemental natural food at any given time is a beautiful thing to the busy fish breeder!

And yeah, my experience indicates it performs a similar role for adults fishes.

In the wild, creatures like hydracarines (mites), insects, like chironomids (hello, blood worms!), and copepods, like Daphnia, are the dominant fauna that fishes tend to feed on in these waters.  There's a lot of cool information that you can uncover when you deep dive into scientific information on our fishes- particularly gut content analysis of wild fishes.

Gut content analysis of fishes which inhabit leaf litter habitats reveals a lot of interesting things about what our fishes consume.

In addition to the above-referenced organisms, organic detritus and "undefined plant materials" are not uncommon in the diets of all sorts of fishes. This is interesting to contemplate when we consider what to feed our fishes in aquariums, isn't it?

It is. 

Anyways, these life forms, both planktonic and insect, tend to feed off of the leaf litter itself, as well as fungi and bacteria present in them as they decompose. The leaf litter bed is a surprisingly dynamic, and one might even say "rich" little benthic biotope, contained within the otherwise "impoverished" waters. I find this not only fascinating- but a fact that we as aquarists can embrace to create aquariums capable of supplementing- or even sustaining-our fishes via the nutrition they can provide.

And, as we've discussed before on these pages, it should come as no surprise that a large and surprisingly diverse assemblage of fishes make their homes within and closely adjacent to, these litter beds. These are little "food oases" in areas otherwise relatively devoid of food. The fishes are not there just to look at the pretty leaves!

They're there to feed and take advantage of the abundant and easy-to-access food resources.

And of course, it goes without saying that Nature works (if allowed to do so) in a similar manner in the aquarium!

The leaves and botanicals we add to our tanks do what they've done in Nature for eons: They support the basis for a surprisingly rich and diverse "food web", which enables many of the resident life forms- from bacteria, to insects...right up to our fishes- to derive some, if not all of their sustenance from this milieu.

Confession time?

Okay.

I've created botanical tanks for years with part of the intention being to see if I can support the resident fishes with minimal external food inputs.

That felt better.

My rationale was that, not only will the leaves and botanicals help foster or sustain such "food webs" as they do in Nature, but that the lower amount of external food inputs by the aquarist helps foster a cleaner system, which is especially important when one takes into account the large amount of bioload decomposing leaves and botanicals account for in the aquarium!

And guess what? It works.

Just fine.

I've done this about 8 times in the past two years, with great results.

A beautiful case in point is one of my recent little office aquariums; a "nano" tank which was "scaped" only with  Texas Live Oak Leaf Litter,  Yellow Mangrove Leaves, and Oak Twigs.  (I know, we're currently awaiting a re-supply of Mangrove leaves any day now!)

Now I know that this tank isn't everyone's idea of aesthetic perfection..I mean, it's essentially a pile of  fucking leaves...However, to the fishes and other life forms which reside in the tank, it's their world; their food source.

And it's reminiscent of the wild habitats from which they come.

In that tank, I maintained a shoal of 25 "Green Neon Tetras", Parachierdon simulans, in this tank. This tank was  up and ran about 8 months without a single external food input since the fish were added to the tank.  They were subsisting entirely on the epiphytic matter and microorganisms found in the leaves...Nothing else.

And they were as active, fat, and happy as any Green Neons I've ever seen.

In fact, they more than doubled in size since I first obtained them. Some of the fishes were shockingly emaciated and weak upon arrival, were rehabilitated somewhat in quarantine, but weren't "100%" when released into the display (yeah, I know- NOT a "best practice", but it was intentional for this experiment).

After a few weeks, this point, I couldn't tell them apart from the rest of their tankmates!

Oh, and they spawned twice!

Perhaps just luck...but weakened, malnourished fishes generally don't reproduce in our aquariums, so I think that something good was going on there!

Now sure, this was a relatively small population of little fishes in a small tank. The environment itself was carefully monitored. Regular water exchanges and testing were employed.

All of the "usual stuff" we do in an aquarium...except feeding.

Of course, I don't think that such a success could be replicated with fishes like cichlids or other larger, more predatory type fishes, like Knife Fishes- unless you utilized a large aquarium with a significant "pre-stocked" population of crustaceans, insects, and maybe even (gulp) "feeder-type" fishes.

I mean, I suppose that you could do this...

However, it is really a more successful approach with fishes like characins, Rasbora, Danios, some catfishes, Loaches, etc.-Especially the little guys.

So yeah, I believe that this concept is entirely replicable, and can be successful with many fishes.It's not some "miracle", or an excise in "giving hobby convention the middle finger"- it's simply a way to set the stage for an aquarium to provide for its inhabitants' nutritional needs.

By stocking your new aquarium with a healthy allotment of leaves and botanicals, perhaps "seeding" it with beneficial bacteria, worms, micro crustaceans, Paramcium, etc., and letting the tank "run in" for a few weeks prior to adding your fishes, you're doing just that.

That's the hardest part of this whole idea. Letting Nature do some of the work.

It requires patience, observation, and some planning. Yet, it's entirely possible snd not hard to execute. It may require creating tanks which embrace a completely different aesthetic AND function. Stuff like detritus, turbidity, decomposition, and biofilms will be things that you find not only interesting, but helpful and desirable, too.

To some extent, it's certainly a bit "contrarian" as compared to standard aquarium practice, I suppose. However, it's not all that "radical" a concept, right? I mean, it's essentially allowing Nature to do what she does best- cultivate an ecosystem...which she will do, if given the "impetus" and left to her own devices. 

And it's not really "benign neglect", is it?

It's the facilitating of a process which has been going on in Nature for eons...a validation of what we experiment with on a daily basis in our "tinted" world. It's that "functionally aesthetic" thing again, right?

I think that, as we evolve into the next "era" of botanical-style aquarium practice, we'll see more and more interesting collateral benefits and analogs to the functions of natural aquatic ecosystems. We need to explore these characteristics and benefits as we develop our next generation of aquariums.

We invite you to experiment for yourself with this fascinating and compelling topic!

Stay inspired. Stay thoughtful. Stay curious. Stay patient. Stay skeptical. Stay observant..

And Stay Wet.

 

Scott Fellman

Tannin Aquatics 

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