Some Background: I've recently had to move my tree frog Bas into a small critter keeper due to tank problems. I have another paludarium lying around, it has a large water area in the bottom with some endler's guppies in there. It's all filtered, with an airstone and i do a water change every week. In my grey's old tank, he would often sit in his pond at night.

Questions:
ive read that grey tree frogs are mildly poisonous? Is this only when they're handled/stressed? or are they just constantly poisonous?
Anyone ever kept tree frogs (especially grey tree frogs) with fish? Can it be done?