Q: How can I tell the male from the female?
A: The nice thing about livebearers is that males have a "sex organ" called the gonopodium. It's a specialized fin protruding from the underside of the fish, and if you look closely, males can direct the gonopodium towards the female in the act of courtship. The gonopodium serves as a tube that transmits the sperm into the female. In the female, this ventral fin is fan-shaped.
Male Guppies are smaller, more colorful, and the fancy ones have extended fins compared to the female. Male Swordtails have longer swords, some females don't have swords at all. Male Mollies and Platys are smaller and slimmer than the females.
Bookmarks