How do i know they are ready?

[Mommy put]

I just bought some Molly's and guppies this weekend, and 1 Molly and 1 guppy are pregnant. I have never tried to intervene with the pregnant live bearers before, I didn't know what to do. So the woman at the store told me just put them in the "2 in 1 floating hatchery" and the fry would drop to the bottom where they would not get eaten and then I could take the moms out. That was Saturday, and still no fry! I can't stand watching the moms in that tiny space any longer, maybe they aren't ready yet? But the guppy looks huge and I can see all the little fry eyeballs back there. The Molly is black to begin with so I can't tell. Are there any other behaviors I should watch for to separate the, before its too late? And will the fry really grow in that little floating space or should inset up a little nursery tank? Thanks so much for any advice!

 

[roydesilva]

Their bottom of their belly becomes square shaped when their close to giving birth

 

[Cr85dirtbik]

Maybe post some pics?