Martinez et al. (1996) related that growth of fish is a complex process affected by many abiotic factors and the temperature is recognized as one of the most important. Furthermore, in captivity, the determination of optimal environmental conditions to reach the best growth performance is essential for the maximization and optimization of its production (AZAZA et al., 2008). Effects of water temperature on growth and development of fish have been well documented for many species, but studies have not been done fitting growth curves for Nile tilapia strains cultivated at different temperatures.