hello,
i have succesfully bred my mollies many many times... it usually takes my fry about 2 months to be grown to the extent that they wont be eaten.. usually my female molly has about 30-50 fry... depending on wether its her first ofspring ... for example when my female first bred i only got about 20 give or take.. but now shes having about 50 every 2-3 months... out of the 40-50 she has only about 20-30 make it to the age where i can give them on or move them to the main tank..when i had my first batch i only got about 5 and i still have 3 of them now ( 2 years on ))... so good luck
are you moving the fry to a seperate tank or a breeder box ??
because i found when i used the breeder box the fry's growth stunted due to the lack of space this 'stunt' meant that they could never be released to the main tank as they never grew.. but now i move the fry to a seperate tank where there is no threat of being consumed they can grow to the perfect size and be released with the rest of the family