The bluntnose minnow preferred the clearer creeks, with gravel or gravel-silt bottoms, but occurred rarely in the mainstream of the Big Blue River. Males and females in high breeding condition were taken on July 14, 1958. The temperature of the water was 75.5 deg. F. =Pimephales promelas= Rafinesque, fathead minnow: Meek (1895: 136); and Evermann and Cox (1896:397-398). All stations excepting 1-S, 4-S, 12-G, 30-M, 43-S, 44-S, and 56-S. Small muddy streams were preferred by _P. promelas_; however, the fathead minnow was taken in all habitats, and in association with most other species. Canfield and Wiebe (1931:6-7) may have recorded _P. promelas_ from the Big Blue River Basin, Nebraska, as "blackhead minnows." =Campostoma anomalum plumbeum= (Girard), stoneroller. All stations excepting 1-S, 2-S, 3-S, 14-S, 15-S, 21-G, 22-G, 28-G, 30-M, 33-M, 34-M, 35-M, 36-M, 37-M, 38-S, 41-S, 44-S, 45-M, 51-M, 52-S, and 55-M. Stonerollers were usually taken in riffles with gravel-rubble bottoms. Those individuals collected in areas with mud or sand bottoms were almost invariably in the current, or in the edge of currents. Specimens from the Big Blue River Basin have an average of 47.4 scale-rows around the body (range 42-54). =Ictalurus melas= (Rafinesque), black bullhead: Evermann and Cox (1896:387) as _Ameiurus melas_ (Rafinesque); and Canfield and Wiebe (1931:5-7, 10) as "bullheads." Stations 2-S, 6-S, 7-G, 11-G, 16-G, 20-G, 22-G, 23-G, 24-G, 28-G, 35-M, 40-M, 51-M, 53-S, 55-M, 56-S, 57-M, and 58-G. Black bullhead occurred in all habitats, but were less commonly taken in the Big Blue and Little Blue rivers than in other streams. =Ictalurus natalis= (LeSueur), yellow bullhead. Stations 7-G, 9-G, 10-G, 11-G, 17-G, 18-G, 19-G, 34-M, 35-M, 36-M, 37-M, 40-M, 47-M, 48-M, 53-S, and 55-M. The yellow bullhead inhabited the muddy-bottomed streams and the upland, gravelly creeks, usually occurring in the headwaters. I obtained only one _I. natalis_ in the sandy Big Blue River. =Ictalurus punctatus= (Rafinesque), channel catfish: Cragin (1885:107); Meek (1895:135); Evermann and Cox (1896:386); and Canfield and Wiebe (1931:6-7, 10) as "channel catfish." Stations 1-S, 2-S, 3-S, 4-S, 5-G, 6-S, 7-G, 8-S, 9-G, 11-G, 14-S, 15-S, 16-G, 18-G, 25-S, 27-G, 30-M, 35-M, 38-S, 39-S, 41-S, 42-S, 43-S, 44-S, 46-M, 50-S, 51-M, 52-S, 53-S, and 56-S. Channel catfish were most common in the larger, sandy streams, but occurred in other kinds of streams. The ages and calculated total lengths at the last annulus for 40 channel catfish were: I, no fish; II, 7.3 (16); III, 10.6 (5); IV, 12.3 (5); V, 13.3 (6); VI, 15.5 (4); VII, 18.0 (3); and VIII, 21.9 (1). These lengths are slightly lower than averages reported by Finnell and Jenkins (1954:5) in Oklahoma impoundments.