Instructions
Check for the seahorse's coloring. Female seahorses possess vibrant or bright coloring. This might not be evident until one compares a male and female seahorse side by side. Male coloring is darker, duller and more subdued overall than the female's coloring.
Compare male and female seahorses in size, if possible. Males are smaller, whereas females are larger.
Look at the angle of the abdomen as it slopes toward the tail. A female will feature a sharper curvature between the belly and tail, as no pregnancy pouch is present. A male seahorse's abdomen curves at a soft arc toward the tail.
Examine the seahorse for a pouch beneath the anal fin. Female seahorse anal fins dangle freely beneath their bellies. Male anal fins hang directly over top of the pregnancy pouch.
How Can You Tell If a Seahorse Is Male or Female?
Determining the sex of seahorses differs from sexing other mammals. Male seahorses possess a pregnancy pouch, rather than female seahorses, which switches the way one would ordinarily check for male and female gender traits. Females also have coloring qualities that one would associate with male animals of most other species. Seahorse sex traits do not necessarily alter parental roles in seahorses, as the female must still contain eggs. But instead of the male impregnating the female, the female lays eggs in the male, and they grow in his birthing pouch.