Self-sustaining Tanks.

[eschaton]

So, I've been thinking a lot lately about tanks which, one way or another, sustain themselves. I can think of three feasible options here.

Self-Reproducing Tanks:

Essentially, create a community of fish and inverts easy to breed, which do not need babies raised in isolation. For example, a tank of Endlers, Cherry Shrimp, Cajun Dwarf Crayfish, and Malaysian Trumpet snails. They would breed readily, not predate on each-others young, and no new stocking money would need to go into the tanks. Planting status isn't super-important, but hiding spaces for young ones suggest planting would be the best.

Self-Feeding Tanks:

In this sort of tank, less emphasis would be placed on reproduction, and more on maintaining a population of fish and inverts without ever feeding them. Heavy planting is a must - the tank should probably have no fish in it for many months, and have purposeful infusions of micro-life like cyclops, planaria, and other algaevores and detrivores. Algae-eating shrimps, small snails, and Otocinclus have been kept in unfed tanks successfully and could very well thrive. The crucial question is if the "microinvert" population could ever get large enough to support a small carnivorous fish or two.

Both in One

I'm not even sure if this is possible in freshwater - unless you create a huge, massively understocked tank. It would be an awesome experiment to try.



Anyway, I'm not claiming anything like an "ecosphere" is possible here, just wondering how close you can emulate real ecosystems in a freshwater tank environment.

 

[KraKen]

The self reproducing tank would actually be the opposite of a sustainable tank, since there are no methods of controlling the populations of the creatures it would soon become overcrowded and the creatures would end up inadvertently killing themselves. A real world example of such a thing happening is the human race, we have not learned how to handle our growing overpopulation and the planets ecology is suffering as a result of this.

As far as the self feeding tank goes, I'm going to try such a thing with ottos, dwarf puffers, amano shrimp, pest snails, algae and live plants, placed in direct sunlight. This could work eventually if I do it right.

 

[GuppyDude]

You'll still need to do water changes in both cases.

 

[Lynden]

I haven't tried something like this in freshwater, but in a ten gallon marine tank I had (now removed) there was such a population of isopods that it sustained a full grown molly. The isopods multiplied on massive amounts of hair algae, which, though not exactly attractive, was very interesting to look at. I fed the tank perhaps once every two weeks, yet the molly was (and is) as fat as could be.

A real world example of such a thing happening is the human race, we have not learned how to handle our growing overpopulation and the planets ecology is suffering as a result of this

Agreed. We've had (or are in the middle of) our boom... now comes the bust.

 

[raptorrex]

So, I've been thinking a lot lately about tanks which, one way or another, sustain themselves. I can think of three feasible options here.

Self-Reproducing Tanks:

Essentially, create a community of fish and inverts easy to breed, which do not need babies raised in isolation. For example, a tank of Endlers, Cherry Shrimp, Cajun Dwarf Crayfish, and Malaysian Trumpet snails. They would breed readily, not predate on each-others young, and no new stocking money would need to go into the tanks. Planting status isn't super-important, but hiding spaces for young ones suggest planting would be the best.

Self-Feeding Tanks:

In this sort of tank, less emphasis would be placed on reproduction, and more on maintaining a population of fish and inverts without ever feeding them. Heavy planting is a must - the tank should probably have no fish in it for many months, and have purposeful infusions of micro-life like cyclops, planaria, and other algaevores and detrivores. Algae-eating shrimps, small snails, and Otocinclus have been kept in unfed tanks successfully and could very well thrive. The crucial question is if the "microinvert" population could ever get large enough to support a small carnivorous fish or two.

Both in One

I'm not even sure if this is possible in freshwater - unless you create a huge, massively understocked tank. It would be an awesome experiment to try.



Anyway, I'm not claiming anything like an "ecosphere" is possible here, just wondering how close you can emulate real ecosystems in a freshwater tank environment.

there was a thread some time back, about these bio sphere's that you get for sale. totally sealed, mini ecosystems. some have been said to last for 13 years. but in the end they all die. life, on this planet, is so complex in its interactions, that to sustain even the most basic forms of earth life, you need a massive ecosystem. NASA has been trying to do this for decades, without successes. closest thing in fishkeeping, imo, is a well planted tank, some of these can, and do, run without filter, even with fish stock, needing periodic topping up, and water changes.