Tarps, if you really want to raise fry, try isolating your female to her own drop tank, with no other fish present. If you have seen my pinned thread on a molly from drop to drop, you must be aware that until I isolated that female she was in my big community tank for well over 6 months with never a sign of any fry. Once I had her isolated on her own, it was a matter of weeks before I could start recording her drop progress with tons of nice viable fry present. If you do not protect your common livebearer fry rather well, you will never see any. Goodeids, my real passion, break this pattern by having huge fry and little fry predation, because of the size of the newborns. I find that almost any of the goodeids will reproduce quite nicely in a colony situation with no trouble, but that is not true of the more common livebearers.