Reproduction of the fish Poeciliopsis gracilis (Cyprinodontiformes: Poeciliidae) in Coatetelco, a tropical shallow lake in Mexico.

A reproductive analysis of 1225 specimens of Poeciliopsis gracilis obtained through monthly samples from Coatetelco, a tropical shallow lake in Central Mexico, was made. There was an evident sexual dimorphism, including a difference in body size at the onset of reproduction. Sex ratio deviated significantly from unity.