Ok for a green tree frog sitting at the bottom of the tank is pretty bad sign. I have 2 males of the same breed. They are always out and about. They are not a nocturnal species either. They are always out. You have a good sized tank from them. Humidity is perfect. Usually the light doesn't have to much of an impact. Whats the current Temperature? I would also suggest puting a large leaf plant in there (live). They may be caught in the wild and do not like the transition from live to artificial. Is it possible you can take a photo of your setup? -CJ