The hardest thing about breeding mollies is supposed to be preventing it from happening, if you have a male and a female. They sre widely regarded ad prolific breeders, just like guppies. You should actually have more than 1 female ...ratio of 1 male to 2 or 3 females.... So that the male does not chase and tire the one female to death while trying to mate with her. You should also have a plan for the fry. What will you do with them? Head over to the freshwater fish and plants profiles forum - there was a profile added for mollies not too long ago. Very informative of view including details on breeding and care.