Guppy male vs female: how to tell the difference

Guppies breed easily — if you have males and females, you will get fry. Knowing how to sex them helps you avoid surprise babies and plan your tank. The clearest sign is the anal fin: males have a long, pointed gonopodium; females have a shorter, triangular fin. Females also have a dark gravid spot near the vent and tend to be larger and rounder.

We’ve written a full guide to sexing guppies with all the details — including what to do if you want to avoid breeding or encourage it. See also our guppy care guide and breeding for stocking and fry management.