Tilapia Pargo UNAM fry was cultured in five 250 L containers at a salinity of 10 gL^-1 and a density of 50, 75, 100, and 125, and their weight and length gain, TCA and TIC, KM and FCA, and ECA were determined. The highest weight (658.45±0.43 g) and length (38.22±0.38 cm), with a gain of 657.28 g and 35.09 cm at the 50 org 250L^-1 density. However, the greatest gain in length was for the 50 and 75 org 250L^-1 densities (35.09 and 34.53 cm, respectively). The highest TCA was for the 50 org 250 L^-1 treatment with 6.26 g day-1 and the highest TIC value was 0.33% daily increment for both the 50 and 75 org 250 L^-1 densities. The FCA was between 0.0873-0.1052 and the ECA was between 950.20-1,146.04%. It should be noted that survival in all four treatments was above 96%. In this experiment, it was observed that when passing from the density of 75 org 250 L^-1 problems in growth and weight and size gain began to occur.