How long to separate female guppies?

[Lee Miller]

So I want to take a couple of females from a colony situation to match them up with a specific male. I know that female guppies can store sperm. So how long should I keep the females separate from the colony to ensure the fry I get are in fact the fry from the male I put them with?

Thanks in advance.

[Fonske]

How old are the females?  I would separate the females and wait for them to give birth. Then add the male immediately and most of the next batch of babies will be from him.  Guppy females can store enough sperm to drop about 4 to 8 times without a male,   so if you want 100% "clean start", it might take several months of separation. Probably not worth it unless all the prospective parents are very young. 

[Steph’s Fish and Plants]

From what I’ve seen online and stuff, your safest bet is to try to separate the females as young as possible to try and get them before they’ve... done the deed. If you know for a fact that they’ve had babies before or are pregnant, and you absolutely don’t want mixing of sperm, you’ll need to separate for probably several months and have them be by themselves. I’d go until probably 2 months of no babies if I really wanted to be 100% sure that they were out of sperm, but I don’t think I’d be that worried about it. I’d probably wait until after one, maybe two rounds of babies so they’re not actively pregnant and then add the male.

[Justin Campbell]

My females drop every ~34 days, so I think if you went 6 weeks with no babies and she doesn’t look super rounded, you’re good to go. This might take several months though as noted above.

[Lee Miller]

Thanks everyone for your replies. 

[Wesley]

Non virgin females are never guaranteed to use the sperm of only the last male. They can mix any stored sperm packets and quite often they will just simply use old and new though usually after a couple fry drops this ratio shifts to the newer male.

What I would do is put the male with a couple females for a couple days, seperate them after and after 6 - 8 weeks the female should start dropping fry. Raise the fry to two months of age and usually you'll be clearly able to tell the traits you want. Cull the ones you don't want and if you want to keep choosing the male / female pairs to sex them early on.

This method is what I use to continue line breeding some mutts I found that looked really great.