We studied the interaction effect between temperature 23 and 26°C, and replacing fishmeal for soybean meal (SBM): 32, 43, and 56% vs. a diet control on culture performance, thermal behavior, and critical thermal maximum (CTMax) of juvenile Totoaba macdonaldi. Fish were fed to apparent satiation three times daily for 61 days. The results showed that temperature had a significant effect (P < 0.05) on weight gain, percent weight gain, and specific growth rate, which were all higher in fish acclimated at 26°C. The preferred temperature ranged between 26.4 and 27.7°C, significantly influenced by acclimation temperature (P < 0.05) but not by diet. CTMax was influenced by acclimation temperature and SBM in the diet. Fish resistance decreased when the percent SBM in the diet was higher. Information on biological indicators for T. macdonaldi adds to the knowledge of a key Mexican species. Our study demonstrated that the use of SBM as an alternative to fishmeal in the diet and the interaction with temperature as a factor could affect this species' performance.