Bloated grey tree frog?

Hi Everyone!

I'm new over here at Fauna (although I've been hanging out at cornsnakes.com for quite a while). Anyway, I have a question regarding a grey tree frog.

I work at a nature center, and one of the grey tree frogs we have there recently developed what I can only describe as severe edema. She is extremely bloated, and when you hold her on your hand and gently tip her from side to side all the fluid in her body cavity visibly sinks to the lowest point. Its almost as if she is "sloshing." She has since stopped eating and just lethargically sits on low leaves, or the ground. She never climbs around on the glass like she used to. The onset seemed rather sudden, and apparently this happened to one of their other tree frogs in the past (I have only been working there since March).

Does anyone have any idea what could be causing this???

I should also add that I do no know for sure that it is a female....everyone there just refers to her as that. Any help would be greatly appreciated as if there is a problem that can be fixed we would like to do so as soon as possible. Thanks in advance.

Katie