Over the past 25 years, the James River in North and South Dakota has experienced records in minimum and maximum discharge. Our objectives were to compare: (1) the fish community in the main river after dry (1988-90) and wet (1993-2000) years, and (2) the fish community of both the main river and tributaries between dry (1975) and wet (1998-2000) years. In South Dakota in the main river, there were 10 families and 29 species after several dry years and 11 families and 35 species after several wet years. Percichthyidae was the additional family after the wet years. Basinwide, there were 41 species present after the dry 1970s and 50 species after the wet 1990s. Overall, 93% of the species collected in 1975 have persisted. Our results provide some support for the flood pulse concept, and the findings suggest that the fish community can be useful for biomonitoring of prairie streams.