What are the Characteristics of the Bluegill?

Habitat

• Bluegills inhabit freshwater habitats, such as rivers, streams, lakes and reservoirs, that have an abundance of plants and logs to provide shelter from predators. These fish generally inhabit warm, shallow water but will move to deeper water to prevent overheating, if temperatures become too high in the summer months.

Size

• A fully grown bluegill ranges from 6 to 10 inches in length. All bluegills have relatively small mouths for their size. According to the Texas Parks and Wildlife Department, the largest bluegill on record weighed 4 pounds and measured 12 inches; it was caught by an angler in Alabama in 1950. Bluegill size can be affected by population size. Larger populations mean that less food is available, leading to a smaller average size.

Color and Markings

• Bluegills are covered in scales, which usually range from green to gray in color. Markings include darker vertical stripes on the flanks and a large black mark near the dorsal fin. In breeding male bluegills, colors become more vibrant and can include red and purple hues.

Fins

• A bluegill has two dorsal fins on its back. The spiny dorsal fin is connected to the soft dorsal fin behind it. Bluegills have an average of 10 spines in the spiny dorsal fin. The three-spined anal fin is on the underside of the bluegill, just before the tail fin. The bluegill has one long pectoral fin on each side toward the front of the body. Like other fish, bluegills use their fins to move through the water and maintain balance.

Feeding Habits

• Bluegills have an omnivorous diet consisting of vegetation, plankton, insects and smaller fish. Insects and other larger prey are not a part of a bluegill's diet until it nears adulthood. Very young bluegills consume large amounts of midge larvae.

Life Cycle

• Breeding season for bluegills starts when water temperatures reach about 65 to 70 F. Male bluegills start to reproduce at 2 to 3 years of age, but females are not mature enough to reproduce until they are 3 or 4 years old. Bluegills spawn their young through external fertilization; the male plays a significant role throughout the spawning and nesting process. Males create a shallow nest by removing material from sand and gravel beds found in shallow water. When the female has filled the nest with eggs, the male bluegill fertilizes them. Nests are often grouped, having been created close to one another. The male bluegill carefully guards the nest until the young fish emerge from the eggs.