Cichlid fishes are exceptionally diverse, with more than 2,000 species distributed across southern Asia, Africa, and the New World. Recent work has discovered unexpected diversity in the sex chromosomes of African cichlids, which include the most rapidly diversifying lineages of the family Cichlidae. This project will test the hypothesis that sexually antagonistic selection is responsible for both the rapid turnover of sex chromosomes, and the rapid rate of speciation in this group.