Lepomis macrochirus

Body is deep and strongly compressed from side to side. The anal fin, which is loated on the underside of the body just forward of the tail fin and serves to stabilize the fish while its swimming, has 3 spines. Tail fin is shallowly forked. Spiny front part and soft rear part of dorsal fin (located on the back) are united. Rear part of dorsal fin has a large black spot (faint in young). Often there is a dusky spot at the rear of the anal fin. The sides have dark vertical bars (except in turbid water) that may be thin and chainlike on young bluegill. Pectoral fin is long and pointed. Ear flap on the gill cover is black all the way to the edge. Sides and back are olive with yellow and green flecks. Breeding males have a blue head and back and a bright red-orange breast and belly. Maximum length is around 16.2 inches (41 cm).

This species is native to the St. Lawrence-Great Lakes and Mississippi River basins from Quebec and New York to Minnesota and south to the Gulf of Mexico. It also occurs in northern Mexico and Atlantic and Gulf Slope drainages from the Cape Fear River, Virginia, to the Rio Grande, Texas and New Mexico. It has been introduced throughout North America and in many other parts of the world.

Habitat includes warm shallow lakes, reservoirs, ponds, swamps, sloughs, and slow-flowing rivers and streams. Bluegill often are associated with rooted aquatic plants and with bottoms of silt, sand, or gravel. They seldom go much deeper than 16 feet (5 meters). Large individuals seek more open water than do smaller ones. Eggs are laid in nests made in shallow water by males, in gravel, sand, or mud that contains pieces of debris.

Bluegill are active throughout the year. Spawning occurs over an often extended period in spring and summer. Eggs hatch in about 2-3 days. Males guard the eggs and hatchlings. Bluegill often spawn in colonies that may include dozens of crowded craterlike or saucer-shaped nests.