A method of inducing male and/or female infertility in a genetically modified (GM) fish is disclosed. Also disclosed is a method of generating an infertile GM fish with a phenotype and/or genotype of interest. The method involves generation of a GM fish whose genome comprises a foreign transgene operably linked to a fish gonad-specific promoter selected from the group consisting of an ovary-specific promoter and a testis-specific promoter. The transgene comprises a suicide gene selected from the group consisting of a reductase and a photosensitizer, in which the reductase is operably linked to a reporter gene. Infertility of the GM fish is induced if the GM fish expressing the reductase is treated with an effective amount of a reductase-activated cytotoxic prodrug or if the GM fish expressing the photosensitizer is treated with light irradiation.