I got my son a 2 African Dwarf Frogs last December for his birthday. I got them in a tank all set up and ready to go. They are in a smaller tank and the place I got them from said I didn't need to do anything but feed them and add water if needed. I haven't needed to add any water. Today we came home and one of them is upside down floating on the top of the water and he is still alive because he moves every so often. Is he sick or dying?? Is there anything I can do??