My female guppy, gave birth maybe 1 week ago, and that has been the third birth that she did since September. The first fry, was released because they looked big enough. The guppies are not bullying. Then, the female,after one week of the last birth, got a bump on its butt, or the place where the baby comes out. It fell off one day later, and she is fine but I want to ask, what was that and how did it happen?