The sex of fish does not depend on the chromosomes
Sex determination is explained based on different philosophies. In humans, sex is determined based on chromosomes, the X and Y chromosomes. However, unlike humans, determination of the sex of fish does not depend on the chromosomes. There are several factors that could influence the sex. Temperature is a common factor. Certain temperature ranges favor female over male sex, and vice versa. These factors could influence the sex determination, hence it is very flexible. These factors are said to influence the fate of both somatic and germ cells. In this case, if the group of fish has the same or identical genome but incubated at varying temperature, they will have different sexes.