Commercial largemouth bass producers indicate that when water temperatures exceed 29.5 ° C, a significant reduction in feed consumption occurs and that fish lose biomass. Typically, producers feed LMB four times a day until water temperatures exceed 29.5 ° C, after which they feed only once or twice a day as fish do not consumption is drastically reduced. Climate models predict that temperatures will continue to rise approximately 5 ° C by 2100. T he increase in water temperatures over time will inevitably result in warmer water temperatures in the southeastern US. This study assessed growth , feed conversion efficiency, and fatty acid composition of three size classes of northern largemouth bass Micropterus salmoides salmoides ( 80 g, 105 g, and 137 g) subjected to a 35 °C water temperature for 28 days. A completely randomized design was conducted, with ten fish per tank and treatments triplicated. The trial was conducted in 1 80-L tanks in a recirculating system, and fish were fed a commercial diet formulated for largemouth bass consisting of 48% protein and 18% lipid at approximately 0800 and 15 00 hrs daily. The experimental period lasted for 28 days. Water temperature was a significant contributor to the feeding and growth results observed in this study. While the 137 g group did experience some growth, it was not biologically significant (Table 1) . The percent body weight consumed by all treatment groups was less than 0.21% day/d. Feed conversion was best for the 137 g group at 4.0 ± 0.44 compared to 5.5 ± 2.57 and 5.8 ± 2.77 for the 80 g and 105 g groups, respectively. Fatty acid profiles of the groups remained similar except eicosapentaenoic acid , which was lower in the 80 g fish. This study was the first study to examine the growth of northern largemouth bass at temperatures exceeding 32 ° C and indicate extended periods of exposure to 35 ° C or higher water temperatures resulted in thermal stress and the inability of these fish to grow at rates necessary to make them profitable for commercial producers.