Disclaimer: I am not advocating species mixing of any sort, I just wanted to get your opinions on somethings I saw this weekend.

This weekend after doing some birding (saw wood ducks galore as well as a crested night heron) and feeding ducks & geese we went to the Zoo. Anyone who's been to Chicago knows the area around Lincoln Park Zoo (one of the last free zoos in the country) is very nice, and consists of a long stretch of parks, harbors and lagoons. Any way, I like to drop by every now and then and check out their amphibians. They have a bunch of bufo americanus, some bombina, and tincs. All of these species were housed individually in decent enclosures. The next display was nothing new to me been there for years, but after spending time on these forums it rang a new bell for me. In the tank was a Madagascar Leaf frog as well as this huge skink. I forgot exactly what he was, and do not recall where he was from. The display next to them had Hyla Versicolors with some box tortoises I think. I thought turtles carried lots of e coli on them, wouldn't this be potentially harmful to delicate amphibians like tree frogs?

I suppose depending on where the skink is from, these mixtures could occur in nature, but to me, a 3 foot tank seems too small to recreate such things....

What do you guys think? Are there any types of frogs that can be housed safely with each other or other animals?