Objective – To evaluate the effects of sodium chloride to control induced stress in juvenile Poecillia reticulata. Methods – The animals were grown in a closed system, monitored by parameters: temperature, pH, conductivity, turbidity, dissolved oxygen and color. Thermal stress was induced by temperature variation using ice and hydric stress. Stress was induced by temperature variation, using ice and water, after standardization of mortality, NaCl was used as a potential agent for prevention of the harmful effects of stress in different concentrations of 1, 3 and 5g/L. Results – The results showed a beneficial effect of adding NaCl at concentrations between. Without the addition of salt, the mortality was 43% and after use of NaCl, there was a decrease in the mortality of 19 % (1g/L), 24 % (3g/L) and 28% (5g/L), of NaCl. Conclusion – The authors concluded that the addition of sodium chloride, and reduce stress, is a product easily available and inexpensive, which facilitates its use by developers.