Platy's Breeding

Morning Cinders,

Yes...prolific little devils, aren't they?
I would say that it is never too early to separate the boys from the girls....as soon as you can tell them apart, which certainly with your ones that are a few months old, should be quite easy, (although in my experience of platys, they will almost certainly be already pregnant! )

The female platy is generally a bit bigger and looks more rounded with a wider belly. Underneath, both sexes have three fins, two at the front of the body and one towards the rear end. On females, these all look similar whilst on the males the one at the back is smaller and noticeably pointed...it is called the gonopodium.

I have been lucky enough to have a LFS that quite happily takes all my babies. You may find somewhere too, but it isn't likely so don't rely on that being your answer.

Good luck though with all your platys...they really are a sweet little fish

Just to forewarn you, immature females can be impregnated. Female livebearers can store sperm for several months and immature females can store it until they are mature, then use it to fertilise their eggs. So a female fry that has been in the same tank as an adult male will probably already be carrying sperm.

Assuming male platies develop along the same lines as male endlers, the front ray of the anal fin will start to elongate as the first sign of approaching puberty. If your fry are in a different tank from the adults, use this sign to separate the male fry one by one so they are away from the female fry before they become mature enough to impregnate the females.

If the tank only has fry in it, the males will need to have a fully formed gonopodium to impregnate the females. If you can catch them as the gonopodium is just starting to develop (ie the front ray starting to elongate) you'll prevent any unwanted impregnation.