Skin Discoloration on Green Tree Frog

[froginabog]

I have two wild caught green tree frogs that I have had for about four months. Twoweeks ago, I noticed a discoloration on the back of only one of the frogs. It is grayish in color and has spread since I originally noticed the change. It now takes up about ¾ of his back and looks very “blotchy.” It is obviously not a matter of color change, and in fact, when he does change color, it seems to change slightly as well. It is not raised, nor have any texture to it different than the rest of his skin. Otherwise, he is acting normal (eating, keeping weight, being active at night etc) with the exception of burying himself into his moss/coconut fiber for a few hours on two separate occasions. I think it may have been a matter of lack of humidity though, due to the dryer air that comes with the cooler weather this time of the year. I have since increased how often I spray and he hasn’t done it since. Their enclosure is a 20 gallon, filled with all artificial fauna, coconut fiber and some moss. I don’t handle either of them unless necessary and I make sure I wash my hands before I do. My other green tree frog isn’t showing any discoloration. Does anyone know what this could be? I’m really hoping someone can identify it. (I’m trying to attach a photo but it doesn’t seem to be working so I might have to add it later)

Also, I understand that, as a rule, catching frogs from the wild is frowned upon. I have had years of experience with tree frogs before (grays) so I knew what I was getting myself into. I will take him to an exotic veterinarian if need be, but I wanted to start here first.

Thanks!