Thinking about getting into amphibians. Suggestions?

[txdrop]

I have a friend that has a custom made mixed species vivarium 4w x 2d x 4t. But all the species are native to each other and theres only two different species of tree frog that I think are in the same family or order or whatever. The rest of the species are isopods like millipedes, some kind of rollie pollie, two small fresh water fish, and some kind of spring tail. Iv always read not to mix species because of competition and potential stress. Not to mention some amphibians have a toxin. But I think if you do your research and really know what you're getting into it could be done.

Edit: And a snail lol