Is this Viable?

[Alpha]

hello, new member here.

I've heard of this project where you take a medium sized jar, and use it for some fish. typically a few guppies, sealed inside. As part of the project, you would also use a small plant, appropriate for the size of the container, and a snail.

as much as I know about enclosed ecosystems, I am inclined to believe that this kind of project is perfectly safe for the fish and that it'd work out and be maintainable (assuming the project duration of 2 weeks without water changes).

But somebody had told me about this "bioload" issue and how 4 creatures is too much for a single plant.

Can anyone shed a little more light onto this? I'm finding myself very curious.

[domjd05]

I've heard of these sorts of experiments being done.. if done correctly they can go on for long periods of time. I don't know what kind of plant/bioload one should use though.

If any of you get a chance to goto the Boston Museum of Science, I forget the exact room it's in- But I know there's a 30g tank with zebra danios in it (a lousy tank at that..), well anyway, in that room(Lol) there is a plastic see through hollow ball.. probably 6'' in diameter. Inside the ball is water-less than one gallon I'd imagine- and in that ball is nothing but one small twig and a single shrimp. I forget that exact variety of shrimp but it was very small. There was a small pocket of air at the top of the ball.. One of the scientist there came up to me and explained that they just kind of threw it together to see what happened- turns out they sealed it (air tight) 7 years ago! The shrimp had survived and everything appeared to be the same way it was the day they sealed it shut!

[Brhino]

My wife has a present I gave her a few years ago. It is a glass sphere maybe four inches in diameter. Inside the sphere there is a twig with algae growing on it and two tiny shrimp. It's a complete ecosystem so long as the shrimp survive, which they have so far.

So, clearly it's possible, but getting the ratio right would be the trick - if you didn't do that, your animals could easily run out of oxygen, or food, or the water could become too polluted with their byproducts. Shrimp in particular have very very low bioloads compared to fish, so to get the setup to work with fish I should think you'd need a much larger amount of vegetation to balance out.

With that said, two weeks is not all that long, even for an unbalanced system. Fish can survive shipping for several days in a sealed plastic bag and can go more than a week without eating, so even if you didn't have things perfectly balanced I imagine you could make it two weeks if you were somewhat close to balanced.

[Mark Hewitt]

If any of you get a chance to goto the Boston Museum of Science, I forget the exact room it's in- But I know there's a 30g tank with zebra danios in it (a lousy tank at that..), well anyway, in that room(Lol) there is a plastic see through hollow ball.. probably 6'' in diameter. Inside the ball is water-less than one gallon I'd imagine- and in that ball is nothing but one small twig and a single shrimp. I forget that exact variety of shrimp but it was very small. There was a small pocket of air at the top of the ball.. One of the scientist there came up to me and explained that they just kind of threw it together to see what happened- turns out they sealed it (air tight) 7 years ago! The shrimp had survived and everything appeared to be the same way it was the day they sealed it shut!

I can't see how that would work! At the very least the plants need CO2 in order to produce oxygen, no CO2 a dead plant and no oxygen and a suffocated shrimp. So I guess *some* air, however small an amount must be getting through?

[Brhino]

shrimp, just like fish (and people!), produce CO2 during respiration, so that's what the plants are using.

[Mark Hewitt]

shrimp, just like fish (and people!), produce CO2 during respiration, so that's what the plants are using.

Ah yes, good point! I wouldn't have thought that the shrimp would have produced enough CO2 to be converted back into enough oxygen, but it obviously does.