Difference in male and female dalmatian molly fish?

All mollies are quite simple to sex. If you take a look at the anal fin (the one under the belly) then the female fish's fin is like a fan shape that she will fan out and flatten from time to time. The male molly has a anal fin that is shaped like a tube or penis that can be moved away from the body and he can twist it forward to reach the female when mating. Hope this helps.