A complete ecosystem?

[Semnae]

My brother just gifted me a 12 gallon tank with an air filter and gravel included. I'm a biology student, and am somewhat curious about the idea of creating a fully functional micro ecosystem. The tank should be able to exist on its own without any outside feeding, maintenance, or interference (with the exception of adding water occasionally to replace that which evaporates since I'm not expecting it to rain inside my tank). The idea is to maximize biodiversity and make it look really interesting. What should I keep in mind as I attempt this?

[Drumachine09]

That sounds like a pretty cool idea, but i dont think its possible in that small of a tank.

Welcome to AC

[Drumachine09]

I searched the net, and i couldnt find any conflicting, nor supporting information. Infact, i could find ant information at all. Maybe Hobbs will know.

[TehTANK]

This sounds difficult because you would need to find something to replace all of the natural things that take place in a normal setting. Things like cleaning, replentishing, enviorment changes and stuff like that. To keep a complete system like that....I couldn't even begin to tell you where to start.

Does this make sense?

[Drumachine09]

With the amount of space you have in a twelve gallon, it just doesnt seem like you could have enough space to fit everything that you needed for a complete ecosystem.

[Fishguy2727]

It would be easier with saltwater. I have seen small completely sealed round ecosystems that contain a small plant or the equivalent and a couple VERY small shrimps, the whole thing was the size of a baseball. As far as a complete system though it would be easier with saltwater. My 10 gallon planted tank wa s pretty close though. It had a ton of plants, 4 white cloud mountain minnows, about 6 algae eating shrimp, and eventually a betta. For a few months all I did was add water. No food, no water changes, just water and light. The white clouds were slightly skinny, but werten't sick or anything. It would not have worked permanently, I don't think, but it was close. I have heard of many saltwater tanks that are almost self-supporting so it is very conceivable. Could you afford to do it as saltwater?

[Drumachine09]

Back When i was but a wee little one, my baby sitter used to have a 90 gallon saltwater tank. She never fed them. Just water and light. She had alot of fish in it too! That shrimp and plant thing is interesting.

[Semnae]

I'll need organisms that complete the Carbon, Nitrogen, Phosphorus, Sulfur, and Oxygen cycles. This mostly includes plankton, bacteria, and aquarium plants. I will also need decomposers/scavengers to remove anything dead from my tank. I'm not sure if my air filter can mix nutrients well enough to mimic lake turnover. I may have to mimic a shallow freshwater environment that does not turnover. If I intend to have anything more interesting than snails in the tank, I'll need to be mindful of the 10% rule - the biomass of the predator should always be about 10% of the biomass of the prey. With this in mind, I'll have to add organisms with defense mechanisms that can work within the confines of a 12 gallon tank so that the predators do not wipe out the prey. Since the tank already has gravel, I'm thinking of getting some burrowing snails, and then a fish or invertebrate that feeds on those snails. For a very basic food chain, I'm thinking plankton --> snails --> fish.

Edit: I was considering loaches because they are also scavengers, knocking two birds out with one stone, but they might be a bit too big for the tank. Dwarf puffers might be a better approach. Both are aggressive which is bad for increasing biodiversity, so I'm open to ideas.

[Drumachine09]

Hmmmm, maybe i was wrong.

[jeffs99dime]

there are refugium setups for reef tanks. you can build your own too. i saw a diy on it i just can't remember where i saw it though.

[Abbeys_Mom]

Take a look at this.
[Only Registered Users Can See Links.]

[Drumachine09]

You've got to admit, thats pretty dang cool!

[jman]

there are refugium setups for reef tanks. you can build your own too. i saw a diy on it i just can't remember where i saw it though.

i just heard of this today!

[Sasquatch]

I don't think it's possible to create a truly complete ecosystem in any aquarium setup, but a simplification could be possible.

You could probably replicate the lower trophic levels and maybe support 1 or 2 small predators. The trick would be finding organisms that replicate fast enough to support the uppper trophic level and maintain enough biomass to reproduce.

Quick growing plants would be a good start, Hornwort would be a good example, especially since the bits will regrow into whole plants. Then you need something small that will eat the plant. Small crustaceans or snails would be ideal because of their low metabolism. Then, depending on how fast your herbivores breed, you can introduce a predator or two. A small catfish or loach should be ideal.

Another alternative would be to cram loads of decorative feature (rocks, driftwood, underwater castles :hmm3grin2orange: etc...) and just let them get overrun with algae. Then get some small snails, leave them for a while to get the population up. Once the population is decent, put in a fish that eat snails.

It's an interesting challenge, I hope you can make it work. As a fellow biologist, it's definatly peaked my interest.

[minabird]

I don't think it's possible to create a truly complete ecosystem in any aquarium setup, but a simplification could be possible.

You could probably replicate the lower trophic levels and maybe support 1 or 2 small predators. The trick would be finding organisms that replicate fast enough to support the uppper trophic level and maintain enough biomass to reproduce.

Quick growing plants would be a good start, Hornwort would be a good example, especially since the bits will regrow into whole plants. Then you need something small that will eat the plant. Small crustaceans or snails would be ideal because of their low metabolism. Then, depending on how fast your herbivores breed, you can introduce a predator or two. A small catfish or loach should be ideal.

Another alternative would be to cram loads of decorative feature (rocks, driftwood, underwater castles :hmm3grin2orange: etc...) and just let them get overrun with algae. Then get some small snails, leave them for a while to get the population up. Once the population is decent, put in a fish that eat snails.

It's an interesting challenge, I hope you can make it work. As a fellow biologist, it's definatly peaked my interest.

Sasquatch-

I'm doing that right now....accidently of course. My old 5 gal got overrun by both algae and snails. I added 2 otto cats for the algae and haven't fed them since I got them over 2 months ago. I had 4 kuhli loaches in there and didn't feed them for the first week I got them. After about a week, the snail population had decreased dramatically and then I started supplmenting their diet with tubifex worms, peas, flakes, etc for their bedtime snack. I did this for about a month and a half before I moved them into my 28 gal to take care of my snail problem in that tank. But the 2 otto cats are still going strong and appear to be getting fat from all the algae. I didn't think a "self-sustaining ecosystem" would be possible in an aquarium but somehow I managed it with them.

[Sasquatch]

Sasquatch-

I'm doing that right now....accidently of course. My old 5 gal got overrun by both algae and snails. I added 2 otto cats for the algae and haven't fed them since I got them over 2 months ago. I had 4 kuhli loaches in there and didn't feed them for the first week I got them. After about a week, the snail population had decreased dramatically and then I started supplmenting their diet with tubifex worms, peas, flakes, etc for their bedtime snack. I did this for about a month and a half before I moved them into my 28 gal to take care of my snail problem in that tank. But the 2 otto cats are still going strong and appear to be getting fat from all the algae. I didn't think a "self-sustaining ecosystem" would be possible in an aquarium but somehow I managed it with them.

That pretty much exemplified the problem with trying to create a complete ecosystem. With only 2 Otto cats, the algae can reproduce enough to sustain them, but not much more. You add another tropic level (Loaches eating snails eating algae) and with only 4 fish, it all breaks down because the predators are eating all the herbivors. You'd have to limit things to 1 or 2 of the loaches, and probably no Otto's to max snail growth.

If you're satisfied with one or two fish in a 12g aquarium (and a bunch of snails), then it's probably doable.

[Semnae]

I found a freshwater equivalent of the spheres above. If I mimic one of those with my tank, I should be able to successfully create a micro ecosystem. ([Only Registered Users Can See Links.])

Edit: Better yet, I can just buy one of those spheres and break it in my tank. That way I'll be sure I have everything.