Determination of sexual dimorphism in Mystus bleekeri (Day)

Fishes exhibit well marked dimorphism between two sexes (Haq, 1977). Individuals of two sexes of catfishes of the study areas look similar. No report on sexual dimorphism of fishes is available except for the breeding season, when the gravid females become obvious by the bulged-out belly and the differentiation of sexes. For breeding and culture purposes it is necessary to separate males and females rapidly and accurately by the external characters. It was with this end in view the present research was undertaken.