The understanding of the mechanisms that regulate the reproductive function of teleosts is an essential requirement in fish culture. The fish hypo- physis secretes two gonadotropins, the FSH and LH that are responsible for gonadal recrudescence. Gonadotopin act on the gonad throughout specific membrane receptors located in the ovarian follicular cells and in the testicu- lar Sertoli and Leydig cells. Two main compartments are found in the testicle, the lobular and the interstitial.The first one is constituted by the germinal cell surrounded by the Sertoli cells, giving rise to the spermatocysts.The Leydig cells are located in the second compartment and are responsible for steroid secretion. The essential unity of the ovary is the follicle which is constitu- ted by the oocyte and its viteline and follicular envelops. The binding of the gonadotropins to its specific membrane receptors results in gonadal steroi- deogenesis. The production of androgens, estrogens and progestagens triggers spermatogenesis and ovogenesis. In captivity, the lack of certain biotic and abiotic factors may account for alterations on the reproductive mechanism of teleosts, resulting in failure or asynchrony of gamete production and release. This review aims to provide essential knowledge on the hormones involved in fish reproduction, their function and way of action on the target organs. This Knowledge will make possible to control reproduction in captivity and diminish or eliminate the above mentioned problems.