Food habits were examined for the spottail shiner, Notropis hudsonius, in Indiana waters of Lake Michigan from June to October, 1973. Insects were the primary volumetric component of the diet. Chironomus spp. larvae and chironomidae pupae were the most important insect food items consumed. The most important zooplankton organism consumed was the benthic cladoceran Eurycercus lamellatus. Alewife, Alosa pseudoharenqus, eggs were the only other significant food consumed.A monthly comparison of food items taken by spottails showed that Chironomus spp. larvae was an important food item in all months and the primary item in September and October. Chironomidae pupae were important from June through September with greatest percent volume consumed in July, The cladoceran, Eurycercus lamellatus was an important food from July through September, reaching its highest percent volume of the diet in August. Alewife eggs were the major food of spottails in June but were also important in July.Young-of-the-year spottails fed primarily on zooplankton for the first month of their existence, but their diet changed in succeeding months and was similar to that of the adults.Analysis of competition between spottail shiners, yellow perch and alewives revealed important overlap in food items in June, August, September and October. Competition in June was between spottail shiners and yellow perch (100-250 mm) for alewife eggs. In August, the spottail shiner and alewife (140-220 mm) competed for chironomids and the spottail shiner and yellow perch competed for Eurycercus lamellatus. September competition was between spottail shiner and yellow perch (26-100 mm) for chironomids and between yellow perch (26-100 mm) and alewives (140-220 mm) for alewife larvae. Finally, in October, major competition was between yellow perch (100-250 mm) and alewives (140- 220 mm) for alewife larvae.Ball State UniversityMuncie, IN 47306