The Amazonian tambaqui (Colossoma macropomum) are the most important native fish in Brazilian aquaculture. The species is responsible for more than 38% of the national production of fish. At harvest, females are almost 20% heavier than males, therefore are the most profitable sex to be cultivated in tambaqui farming. In order to provide knowledge supporting the development of new technologies for the tambaqui industry, we aimed to evaluate the influence of pH on the sex determination of tambaqui
