Female preferences and male-male interactions in zebrafish (Danio rerio)

Female preferences for male body size, male preferences for female body size, and male-male interactions were experimentally evaluated in zebrafish (Danio rerio) obtained from the pet trade. Female preferences were shown for larger males. Males did not show preferences for female body size. Zebrafish males have strong interactions when two males are placed together with a female. Body length of males and females was not different. These results indicate that the reproductive strategy of zebrafish is more elaborate than simply broadcast spawning: females are choosy and males compete for females. Mate preferences and male-male interactions of zebrafish are discussed and compared with expectations based on sexual selection theory.