They can get over 2.5". I've never kept them, but I understand they are pretty similar in care to the very hardy Gray Treefrogs. They're next on my list of frogs I want

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If you do set out to acquire some Grays in the wild, I would suggest you get them as young as possible and preferably don't remove breeding age adults from the wild populations. Find where they are breeding and go back in the day to look for tadpoles. A week or two after a major breeding event (lots of calling) is a good time to look for tadpoles. Be sure to check with your states laws about collecting.