wolfman21

Does anyone know how early sex can be determined in guppy fry? One of my guppies had about 75 babies and I want to know when I will be able to determine their sex based on the anal fin for females.

Neville

i think male and female guppy fries look all the same, u have to wait until they reach adulthood.

wolfman21

Cool because the young ones I have all look alike and I thought I had all females and was kinda bummed because my LFS said they would take my males, so I was hoping I had some males in there.

bomber822

i have two week old fry and i still can't tell the difference but i wanna get the males and females seperated before they start getting pregnant and i heard i think after or about a month you can tell the difference and that is when they start getting there color but thats also when they get sexualy mature and start having babies

Butterfly

Actually their sexed by the anal fin of the male about four weeks you can usually tell for sure.
Carol

purple_phoenix

I've been able to tell mine at 3-4 weeks. They start showing their colours around then as well

peacemaker92

I've had many guppy fry before and i could tell their sex after their 3 weeks old!

Blackswords

An even quicker way. Females develop the gravid spot before the males develop the modified anal fin.

Butterfly

The males will develop the modified anal fin before the females develop a gravid spot. If their really small a magnifying glass will help tell which is which.
Carol