Abstract: To investigate the swimming performance and swimming behavior during fatigue cycle，we tested the juvenile Aristichthys nobilis′ swimming capability by increasing velocity with mobile Brett-type swim tunnels by LoliTrack，and then assessed the swimming capability of juveniles at different actuating state.Results show that the oxygen consumption rate (M_O2) before swiming fatigue increased with swimming speed significantly. The burst swimming speed M_O2 was higher than the critical swimming speed M_O2.Video analysis displays that there was significant linear correlation between tail beat frequency and swimming speed. Meanwhile，the juveniles showed burst-coast behavior continuously for two tests at the critical swimming speed in the two groups of repeat fatigue. However，during the transition from the test of burst swinmming speed to the test of critical swimming speed，the juveniles did not show that behavior. After the test of the first critical swimming speed，the second critical swimming speed was higher than that of the test of burst swimming speed. Neither of the burst swimming speed in two tests had significant difference. Anaerobic exercise consumption of bighead carp led to significant decrease of aerobic swimming performance，and aerobic exercise had no effect on anaerobic exercise.