Actually, I would say that low 70s is probably better, and can drop down to 60s at night. They are very cold tolerant, and won't like excessively warm, or tropical temps. Mine are at ambient room temp + a little extra warmth from the lighting; about 70-71 degrees during the day, and around 67 at night. They seem very happy, active at night, and eat like pigs.

I would set it up in at least a 10 gallon tank, even if you're just going to keep it over the winter. You can put a live Pothos plant in it, as long as you make sure there are no chemicals on it. A nice piece of cork bark for climbing and hiding would also be appreciated. You can do a gravel substrate with a water table, which will ensure that it remains humid enough. A screen lid should be okay, as this will create a humidity gradient, and enable him to hang out in drier areas, which they often prefer to do.

Depending on the size of the frog, you should be able to feed either large or small crickets from the pet store. If you feed in a smooth sided dish, the crickets won't get all over the rest of the tank. You will want to dust occasionally with vit powder, and with calcium with vit D, but not at the same time.

If you decide to keep it permanently, a 20 gallon tank should be sufficient, well planted, and with plenty of wood for climbing.

Good luck, and what a miracle that he got into your house and survived.

Just FYI, there is a tree frog forum here, Tree Frogs. There is also a Gray tree frog care sheet. http://www.frogforum.net/tree-frogs/...caresheet.html