Sexing Tilapia: An Easy Way to Determine Gender
From selecting for breeding to reducing aggression, there are some great reasons to figure out the sex of your fish. Here's one easy way.
Use dark food dye (green and blue are best) to highlight the physiological characteristics.
The dye accentuates the anus and genitalia of the fish and the difference is clear.
Male tilapia have a tapered shape below the anus, whereas the females have a more rounded shape with a triangular indentation in the center.