Frogs with Darts

If you're going to mix different families of animals of one order, aka dart frogs and any other kind of frog, you need to provide for the needs of both animals. This takes an enormous amount of space, because you have to have two different habitats, etc, and still have enough room that they don't bother one another. I agree that it is good idea to just keep different families of animals seperate. It not only makes logistics much more simple, but the frogs would probably be happier and fatter too, not having to compete for food with another species.

I would never, under any circumstances, mix species from different geographical regions. I wouldn't put a mantella with a red eye, a sulcata tortoise from africa with a gopher tort from america...Mixing individuals which evolved in different locales is a good way to spread disease, encourage species jumps, and so on. The affect of Indo-european diseases on Native Americans when the Europeans arrived to NA is a perfect example of how even the mixing of different geographical populations of the same species can have disasterous results. There are several other zoological examples as well. It's just not a prudent thing to do.