Growth of the annual fish Cynopoecilus melanotaenia (Regan, 1912) based in a temporary water body population in Rio Grande do Sul State, Brazil (Cyprinodontiformes, Rivulidae).

The growth of the annual fish Cynopoecilus melanotaenia was studied in its natural environment, in order to obtain information about its biology. A total of 797 specimens of C. melanotaenia were collected on a monthly basis between April 1994 and March 1995 in a temporary water body, located in Rio Grande do Sul State, Brazil. The growth curve in total length suggests, to both sexes, a fast initial growth. Males present a smaller growth rate than females, but they attain a higher average maximum length than the females.