This document summarizes 3 papers about molecular control mechanisms and hormonal induction of spermatogenesis in fish. The first paper from 2003 discusses molecular control mechanisms of fish spermatogenesis. The second from 1991 details hormonal induction of all stages of spermatogenesis in vitro in male Japanese eels. And the third from 2006 finds that progestin is an essential factor for initiation of meiosis in spermatogenic cells of eels.