Abstract: The present paper describes the developmental characteristics of the sperm nucleus from homologous gynogenetic crucian carp in the fertilized eggs of four types of gynogenetie crucian carp. It was preliminarily revealed that the naturally gynogenetic crucian carp assumes two different kinds of reproductive modes, depending on the sperm sources. The heterologous sperm nucleus remains compact after entering the gynogenetic egg. However, the homologous one shows activation and even partially transforms into male pronucleus. The peculiar biological significance of this phenomenon in maintaining population survival and causing clonal differentiation of gynogenetic crucian carp is discussed.