i have had 1 for 4 months with a male in the tank as well and have just bought another 3 weeks ago i also have 2 black female molliesNot too sure about Mollies, but every other Livebearer I used to keep dropped every month or so. Have you just got females or some of each?. Even if you've only females and they're definitely pregnant, you can look forward to a batch of fry for the next 6-7 months.