Protogyny - the phenomenon of sex change in hermaphroditic individuals. At a young age, the ovarian part of the fish develops, such an individual functions as a female. After several spawnings, their ovary is reduced and the testis develops. Protogyny is an adaptation that ensures population increase in water bodies with unstable living conditions and insufficient food supply.

Protogyny is observed in species of Guban, Parrotfish, and Sea Bass, as well as some Bullfishes.