mollie fry pregnant?

[gareth]

i transferd the remaining fry to their own tank about 3 weeks ago but had to leave one fry in the main tank with the adult mollie

the single mollie fry looks quite plump is it just growth or is the fry pregnant, at what age can fry come into season and how long wil it be before i have to put the pregnant fry into a birthing net

any advice apreciated