I bought a large hermit crab a month ago and have it in a 55g along with a CC starfish (this is my QT tank BTW, that's why there is no fish in there). I woke up this morning to find another crab about 1/2 the size of the large one. This one didn't have a shell. There is no mate in there and I'm certain it isn't a molt. Do hermit crabs reproduced easily?