Makito Kobayashi, Eri Iwata, Peter W. Sorensen
The goldfish, a member of the Cyprinidae (minnow family) is an important and relevant model for understanding how fish function and reproduce and can be better managed. Here, we review recent studies of this species and its strengths as a model system. First, we review current understanding of how its neuroendocrine system regulates gonadotropin release, and then steroidogenesis and finally gonadal maturation in both males and females. Endocrine determinants of gender and sexual plasticity are described. Effects of the fish androgen, 11-ketotestosterone, on sexual and spawning behavior of males and females are reviewed. We also describe how several hormones (androstenedione, 17,20β-dihydroxy-4-pregen-3-one, prostaglandin F2α) and their metabolites function as "hormonal pheromones" to synchronize male-female spawning behavior and physiology. Insight provided by the goldfish has enhanced understanding of the neurobiology, toxicology, and comparative physiology of other fishes and provided lessons applicable to the culture of commercial carp and the control of invasive species, as well as conservation.