The relative importance of interference and exploitative competition from Daphnia was tested in contrast to known role of Cyclops vicinus predation, influencing the rotifer community in Rimov Reservoir during spring period. The abundances of five dominant rotifer species and their birth and death rates were analysed, together with changes in chl-a concentration, HNF, bacteria biomass and the abundances of predator and competitor species, from high frequency sampling. Development of loricated species (Keratella cochlearis, K. quadrata and Kellicottia longispina) was driven predominantly by food availability. The dominant soft-bodied species Polyarthra spp. and Synchaeta lakowitziana were affected predominantly through C. vicinus predation. The role of mechanical interference from D. galeata, although may be important in a limited periods was overclouded by predation and exploitative competition in general.