One of my female molly fish has had a father large belly for about a month now. At first i thought she was pregant, and then she slimmed down. So i checked in the tank for any fry but there where none. She has recently gotten very big again. I haven't seen her mating with the only other male in the tank. She swims normally. What could it be? Could she be preggers and for some reason won't give birth?