It would be best if you converted it to a vertical. A grey tree frog really isn't going to be very happy in a horizontal 10 gallon. I had mine in one for a couple of months before switching to a 24" tall vivarium. Also, it's not always easy to find captive bred grey tree frogs. Many states have laws regarding collecting/keeping/selling/transporting native amphibians. You will have to look and see what your local wildlife laws are.