question on Mollys and breeding

Question
I have 4 adult Molly fish. I'm having a hard time deciding if they are males or females. The one I think is a male keeps raising his top fin up and seems to be pecking at the anal fin on the other fish. Is this aggression, the beginnings of mating etc? I can't really tell if it's fighting or not.

Answer
Hey Lori

Mollies don't fight, they are probably establishing dominance.

mating might start with a certain fish with a long fin underneath its belly, a extended anal fin called a gonopodium which is the male, chasing another fish which would be the female. the antics which are being displayed by your fish may well be the start of mating

Hope this helps and Good luck      Jack