Healthy frogs shed their skin regularly every week or two and often energetically. The old skin will usually be shed in one complete piece and look like a frog “ghost” floating around the tank for a few seconds afterwards. Sometimes the frog will eat it. Sometimes, though, it can be a much more messy process with small pieces of old skin remaining stuck to the frog for a day or so. Things like water temperature, feeding, water chemistry and so on probably influence the manner and frequency of shedding.