The environmental light to which most animals are exposed has a major influence in their physiology. Over the decades attempts are being made to understand the physiological mechanism of the processing of environmental light information in the regulation of various body functions in general and reproduction in particular. Light as a source of environmental cue in the use of regulation of reproduction has also been considered for fish, the study on which has gained momentum because of its tremendous economic importance as food. Thus for obvious reasons efforts are continued to develop...