Effects of water velocities (0,0. 1,0. 3 and 0. 5 m /s) on swimming performances of juvenile tinfoil barb Barbodes schwanenfeldi,weighing 125. 94 ± 13. 87 g,were investigated at the water temperature of 28℃ . Swimming behaviors of the fish were monitored continuously for 90 min by a video tape recorder,and the video data were analyzed by computer packages. The results indicated that rheotaxis frequencies and tail beat frequencies of juvenile tinfoil barb increased with increasing water velocities from 0 to 0. 3 m /s,but decreased at 0. 5 m /s. The time of swimming performances varied obviously at different water velocities. At 0 m /s,the fish kept moving for more than 98% of the experimental time,and at other three water velocities,the fish were in fixed positions against the current (FP) mainly. When the water velocities rose from 0. 1 m /s to 0. 5 m /s, the time of FP increased from 45. 8% to 81. 3% ,but that of moving forward against the current ( MF) decreased from 24. 1% to 5% or less. The time of moving backward against the current ( MB) reached the maximum at 0. 1 m /s,accounting for about 16. 4% of the experimental time. The time of downstream ( DS) accounted for 13. 7% ,2. 1% ,and 10. 9% of the experimental time at water velocities of 0. 1 m /s,0. 3 m /s and 0. 5 m /s,respectively. Tail beat frequencies of the fish showed significantly positive relationship with swimming speeds in the MF and FP performances,but had no significant correlation with swimming speeds in DS and MB performances.