Community impacts of larval walleye (Stizostedion vitreum vitreum) and nutrient addition were examined in an experimental enclosure study. Larval walleye significantly suppressedDaphnia, DiaptomusandCyclops, but enhanced rotifers. Suppression of zooplankton by larval fish alone did not increase phytoplankton blooms unless fertilizers were added. Nutrient levels (NH3-N, NO3N, and PO4-P) were enhanced in enclosures with fertilizer additions, but were not enhanced in enclosures with both fish and fertilizer additions. Fertilizer applications significantly increased phytoplankton biovolume, pH and dissolved oxygen, but did not increase zooplankton biomass. The highest algal abundance was found in enclosures with both fish and fertilizer additions. This could be due to the release of zooplankton grazing pressure by fish together with nutrient enrichment. Our results suggest that larval fish are important in regulating the zooplankton community, but their effects on phytoplankton depend on nutrient availability.