so does it mean that some eggs can be from old mating, and some from new one?
Not that any study done on any wild species will tell us much about domestic hybrids, but further on this interesting topic, most Poecilia can and do have multiple paternity considerations. It's so highly variable, however, that it can depend upon anything from the specific population to the size of the female.
I've always found domestic hyb. Helleri to be ridiculously difficult to 'cleanse' of previous matings, while domestic hyb. Platy's will easily take their latest fertilization almost every time. Whether that's the case with all domestic hybrids I don't know, but the very nature of hybrids would suggest it won't be consistent.
Hey Mr. Mefford, are you about? I'd like to hear if your experiences with domestic Xiphophorus have shown a pattern, if I could please.
Keep us posted, Strikeris. I hope your hyb. Helleri are more cooperative than mine!
Birchmanni are one of my fave wild-type Swordtails. Definitly one worth trying if you venture into wild-types.