ABSTRACT
In fi shes, sex change is a unique but an intriguing phenomenon, especially from the point of genetic basis of sex determination. Instantaneously, this unique phenomenon poses a series of challenging questions regarding the presence of sex chromosome system, and sex determining genes. However, with the present understanding from the PGC/SSC transplantation studies that the bisexual potential is retained by fi shes even after sexual maturity and spermiation, it may not be diffi cult to reconcile with the presence of 367 sex changing fi sh species. Consistently, these sex changers are considered as hermaphrodites and their presence is limited to tropical coral reefs. Nevertheless, simultaneous possession of ovarian and testicular tissues in gonads among cichlids (Peters, 1975) and sex changes in some cichlids (e.g. Crenicara punctulata, Zupanc, 1985) and anabantids (e.g. Macropodus opercularis, Koteeswaran and Pandian, 2011) are also known. Yet, the sex change in sequential and serial hermaphrodites is a natural genetic phenomenon but in cichlids and anabantids is perhaps a social pressureinduced phenomenon.
