I was doing some reading today and saw a forum discussing ecosystems. They had a site to build your own (don't recall) on a marine or dry land one.
Has anyone ever tried or know how to make a freshwater one. I read on it abit but they wanted you to use a 10G and I think I have seen them in an enclosed glass jar, never needed anything.
Just was wondering... I am on a trial attempt to start one. Even if I fail, I won't lose any $.
I started with some cleaned sand, the kind you mix into cement. Then I grabbed some gravel from an established aquarium. I went out to my pond, and grabbed a bucket of water and debris from the bottom.
I added a small layer of the gravel, then sand, and some of the pond water. Then I added the bottom contents of the pond water. Old leaves, and who knows what else. Unfortunately I didn't get very much sludge. My pond is cemented and small.
I added more of the pond water, then a small bit more of the gravel. Just a tad of tap water. Now I have an air stone going in this solution. Supposedly it is supposed to clear the water up in 24 hours...
I am now in the waiting 24 hours part.
There is supposed to be bugs or planaria or bacteria or whatever in the pond water already I guess.
oh, yeah, the stuff really stinks.
Any help out there?

I think I know what you are talking about.. I read a post a long time ago about someone that had a teacher that had done an experiment on that. He said he used guppies, and by the time the school year was over, they had very stinky water and a lot of guppies. It seemed to work though, so they say. The nice thing about saltwater is it actually COMPLETES the nitrogen cycle. It uses the nitrate also. I guess that's why it's easier or more popular.

I've read about a snail in a 'snow globe' type environment. Not sure how it would work out with a fish.

I don't really understand what you are going for here?

an ecosystem, a completely enclosed environment where nothing needs help. it survives by itself. in other words a sealed container of a life system, in which no water changes, no feeding, anything from the ecosystem balances out itself.

I can see it happening...but not without live plants and lots of light. Plants are part of the cycle of life and if all you have is detritus from your pond it's probably not gonna work.

These systems are called "Biotopes". I would imagine their is a ton of stuff on Google to help you out.

Sounds very interesting I can't wait to see how it turns out.