It is most abundant in clear lakes with large amounts of aquatic vegetaion. However, it occurs in a large variety of habitats including pools, overflow ponds, oxbows, swamps, and man-made impoundments. They often occur in small loose schools that have up to 20 to 30 individuals in them. They are generally small to medium-sized fish.
Bluegills are generally carnivorous.
When other food is in short supply, they will also eat algae. These nests are shallow, circular depressions and are frequently in areas with gravel bottoms. Often many males build nests in a small area. Females lay eggs in the nests. The males then guard the eggs until they hatch.