Snails are a major food item in adults, which they crush with pharyngeal teeth, giving rise to the vernacular name shellcracker. In some small ponds, redear practically eliminate snails. The males build a nest, usually grouped into colonies near submerged vegetation. Females have an average of about 20,000 eggs, but as with other sunfish it is unlikely that a female deposits all of her eggs in one nest. The eggs hatch in 6 to 10 days, and the fry remain in the nest guarded by the male.
Redear growth is more rapid than bluegill.
Most redear mature in the second year of life.