Diet of Minnow Chrosomus erythrogaster (Cyprinidae) in a Minnesota Stream

The minnow Chrosomus erythrogaster was noted to feed chiefly upon microscopic plants of the Divisions Cyanophyta, Chrysophyta, Euglenophyta, and Chlorophyta in the headwaters of the Zumbro River, Dodge County, Minnesota. Diatoms (Chrysophyta) were apparently the most important food items. Indigestible materials, both organic and inorganic, were freely consumed. Food items generally corresponded to what was available in the stream. Feeding activity was higher in daytime than at night. An aquarium experiment indicated that small fishes such as C. erythrogaster are capable of influencing the population of available food organisms.