In my 25 gal tank two of the molly fry are now in the main tank, both appear to be female. Today I released the two platty fry also as they were starting to get rough with each other in the breeders net. After releasing them I realized one was male and the other, a female, has a much rounder, slightly bulging belly. The fry net has too much algae on it atm to get a good look at the fish from the side.

So could the female platty fry be pregnant already, or is it likely just another stage of development. And how long before I need to remove the male completely from that tank to prevent him breeding with the adults? The fry are probably at least a month old possibly as much as a month and a half. I found the platties after they had been in the tank for at least a week or two so don't really know the exact age. They are 1/2-3/4 inch long atm, and almost as fat top to bottom as they are long.

Any help, info appreciated as these are my first livebearer fry.

I am not sure but I think it is somewhere in the 6 month range or it might even be a year, but I am not sure. I know it is a lot younger than when humans can though because mine were the same way! I hope that helps you in answering your questions

you can tell when they're pregnant if there is like a dark area by the abdonem or somewhere around there, i dont fully remember

they can already breed when the juvenile males develop the gonopodium.

Well his is definitely developed. The adults are still looking at them like they might be good for a snack so he will probably stay away from them for a while. But the female fry/juvenile might already be pregnant then? I really don't know how old they are other than thay cant be over 2 months as thats about how long I've had the adults.

Thanks for your help.