I don't have much experience with tads, but I was watching a friend's pets while she was on vacation for two weeks, and her tad in an aquarium fully gained its legs while I was taking care of them, so I moved it to a tank of half land, half water, and within just a few days the tail was completely gone. As far as the mouth goes...I paid no attention at all. I was focused on the legs. Maybe someone else could provide a better answer.