My White's have been living in my fish tank for four years now. No problem. I have witnesses my red-eyes under water in the rain chamber's reservoir. I have chased gray treefrog in my yard, who jumped into the pool and swam to the bottom. So treefrogs and water are a good mix, as long as they have places to rest on. If you don't quite believe it check out "Frog and Toads Your Happy Healthy Pet" 2nd edition, page 44. There is a picture of MY frog and set up on that page, so you can see exactly what my set up looks like.

My frogs have yet to eat any of their tank-mates.