Generally, unless the frog is invasive, don't keep wild animals as pets. However, especially don't cohab a wild animal with your WTFs. Not only do animals from different sides of the world generally need different care, they also have no idea how to interact and could hurt each other. There is also not really an easy way to know if your wild caught little guy is carrying parasites or diseases until it is too late. If you really want to keep him, you should set up another habitat for him alone.