I put a 1/2 Black Red female in my 10 gal berthing tank 4 days ago. After 48 hours she dropped 3 fry in about 2 hours, then nothing, but still pretty big, with a dark gravid spot. I kept her in the berthing tank for another 48 hours, then put her back into her display tank with the male 1/2 Black Red.
2 days ago I put a Red Delta female into the same berthing tank, and today she dropped 20 fry and looks spent. I'll keep her there another 24 hours, then put her back into her display tank with the Red Delta males.
Still haven't figured out why some of these females drop all at once, and others dribble out 2-3 at a time over the course of many days.