I have a gray tree frog who's recently appeared to get very swollen or bloated. His entire body and legs look very big and swelled up and his throat sack is always inflated and hanging down. He's not just fat, I haven't been over feeding him. And he as also stopped eating.

I don't know what I should do.

More details:
I've had the frog almost three years
Temps range about 77 F daytime
humidity 50-60%
Substrate coconut fiber
Live plants pothos and ficus
Glass tank with cork bark flats, and a plastic water dish.
Nothing in his environment has changed recently.
Diet B. dubia roach nymphs and an occasional moth
Only one frog, no cagemates.