shaliser

I don’t know much about red-eyed tree frogs, but some types of frogs change color due to moisture. There is a chance it could be too moist but I doubt it, I would call the store if it was me. it may have gotten sick at the store or somewhere else, if so there is almost no help, frogs don’t usually show they are sick until it is too late, I learned that the hard way. it may also just be stress, but I would still call the store and see what they say.

Frogs change colour for heaps of different reasons, humidity, lighting, the background colour (how light/dark everything is in your tank) and stress.
He might just be sleeping, because they sleep in the day and are active at night (mostly). He probably is breathing, you just cant see it, but keep an eye out (like you are) to see what else happens. try not to nudge him too much because it might stress him out (with being moved into a new home and all) just let him settle in and make sure his eating and pooping and he should be fine, good luck
Its good that your worrying about this though, because as froglover said, once you can notice the signs of illness its usually to late.

im sure that the frog is sleeping just let it be so it doesn't get stressed out.