I have 2 common grey tree frogs in a separate tank and this particular green frog here hasn't grown OR changed color at all, like my common greys do, the entire year I've had it. I don't think it's a common grey tree frog. I'll have to get some better pictures and maybe someone would be able to identify it by that. The one I provided is blurry. I haven't heard any calls from it either. My commons keep me up nights at times!
By the way, this green one was found in the same area I found the spring peepers. I understand it's debatable on mixing species but I also think it's not really harming much (minus the parasite issue, that I agree with) with this particular arrangement. I would never put small frogs in with large ones. That's why I was keeping this small green one with the peepers and the tank I have them in is pretty large. Once I can convince my husband to build me my own critter room/greenhouse, I'll get a separate tank for it.