Diel feeding patterns of subadult and adult cyprinids of three species (roach Rutilus rutilus, bream Abramis brama, bleak Alburnus alburnus), which foraged almost exclusively on microcrustacean plankton, were studied in the meso-eutrophic Římov Reservoir (Czech Republic). All cyprinids showed a daytime feeding periodicity, with a marked night-time decline in gut fullness. Diel variations in gut fullness were observed in roach 200–270 mm standard length (SL) and bream 220–330 mm SL during May and in bleak, roach and bream of 110–170 mm SL, respectively, during August. Our results corroborate other studies in which light intensity has been found to be an important factor affecting cyprinid foraging on zooplankton. Daily zooplankton consumption rates ranged from 1.5 % of wet body weight in bream (220–330 mm SL) to 9.9 % of wet body weight in bleak (110–170 mm SL).