I have 1 adult in a ~13 gallon which I feel she's outgrown (a ~29 gallon is nearly grown in enough for the move), so I'm of the opinion that 5 gallons is too small for one adult, and certainly too small for 2. I have pictures in my albums of my vivariums. I'm a fan of way more plants than you have. Lots of cover for hiding and lots of different perches for them to hang out on.

As for the breeding, I can't be much help as my experience is with the lone one I have (they're also not native where I am). I'm pretty sure mine is a she due to lack of calling and she didn't appear to be carrying eggs over the winter when kept at room temperatures that regularly dipped to 14C (~57F). "She" could still be a quiet "he" though. Definitely don't simulate a rainy spring season:P.


Quote Originally Posted by Kristen View Post
It isnt really illegal in America (though some states vary I think), their laws are alot less strict that ours.
It varies not only by state but by breed of frog as well.

Quote Originally Posted by Kristen View Post
General rule of them is TEN gallons per frog, though I think its less for American Green tree frogs as they are tiny.
But I don't know either. It's best to get advice from someone who keeps them.
Hyla cinerea are small compared to the "Green treefrogs" from down under, but they are also quite acrobatic!