Circannual, diel, and lunal periodic mechanisms in naturally reproducing stocks of tropical and subtropical fishes are reviewed. Manipulations of biological clocks, used to control reproduction in captive broodstocks, are detailed. Experiments to induce controlled maturation and spawning in fishes either test efficacy of changing environmental conditions (regimes), or constant environmental conditions (controlled). Data have been generated in experimental/scientific studies, as well as applied research. Effects of controlled environmental regimes on serum steroids, gametogenesis, spawning, fry performance and egg quality are summarized for selected members of Centropomidae, Serranidae, and Sciaenidae.