Abstract o 1. RoutineV0307O 2 were determined for six MDH-B genotypes of red shiner, Notropis lutrensis (0.24–1.42 g) at 10 and 30°C. 2. V0307O 2 were significantly correlated with fish weight at 10, but not at 30°C. 3. V0307O 2 were significantly higher at 30 than at 10°C and the mean Q 10 from combined data was 2.04. 4. Variations in MDH-B genotype were not significantly reflected inV0307O 2 of this species.