Lepomis purpurescens Cope, 1870 The bluegill (Lepomis macrochirus), sometimes referred to as "bream", "brim", "sunny", or, as is common in Texas, "copper nose",[3] is a species of North American freshwater fish, native to and commonly found in streams, rivers, lakes, ponds and wetlands east of the Rocky Mountains.

The fish are important prey for bass, other larger sunfish, northern pike and muskellunge, walleye, trout, herons, kingfishers, snapping turtles and otters, and play a key role within the food chain of its freshwater ecosystem.

A popular panfish among anglers, bluegill usually hide around and inside old tree stumps in swamps and other underwater structures (e.g. snags), and can live in either deep or very shallow water.

Bluegills also like to find shelter among aquatic plants and in the shade of trees along banks, and will often move from one cover to another depending on the time of day or season.

The bluegill is noted for the large black appendage (the "ear") on each side of the posterior edge of the gill covers as well as the base of the dorsal fin.

[3] The bluegill occurs naturally in the United States east of the Rocky Mountains from coastal Virginia to Florida, west to Texas and northern Mexico, and north to western Minnesota, New York and southeastern Ontario.

In the case of Japan, bluegills were presented to the then-crown prince, Akihito, in 1960 as a gift by Richard J. Daley, mayor of Chicago.

[12] In the summer, adults move to deep, open water where they suspend just below the surface and feed on plankton and other aquatic creatures.

Bluegill try to spend most of their time in water from 60 to 80 °F (16 to 27 °C), and tend to have a home range of about 320 square feet (30 m2) during nonreproductive months.

[13] Young bluegills' diet consists of rotifers, copepods,[14] water fleas, and insects (mainly chironomids).

Herons, kingfishers,[15] and otters have also been witnessed[citation needed] catching bluegill in shallow water.

[15] Bluegills have the ability to travel and change directions at high speeds by means of synchronized fin movements.

Bluegills have a lateral line system, as well as inner ears, that act as receptors for vibration and pressure changes.

[18] The bluegill sunfish relies heavily on the flexibility of its fins to maintain maneuverability in response to fluid forces.

The bluegill's segmentation in its pectoral fin rays mitigates the effects of fluid forces on the fish's movement.

[23] When swimming backwards, the bluegill utilizes a plethora of fin muscles located in various parts of its body.

[24] The pectoral fins' rhythmic beat is asymmetric and aids the fish's balance in its slow, backward movement.

[24] The bluegill, amongst a wide array of other fishes,[25][26] exhibits the C-start escape response, which is generated by large neurons called Mauthner cells.

[27] Mauthner cells operate as a command center for the escape response and respond quickly once the neural pathway has been activated by an initial stimulus.

[28] The C-start escape response produces other advantages, including the ability to move quickly and unpredictably to capture prey.

[27] Hydrodynamically, the bluegill exhibits specific flow patterns that accompany its C-start escape response.

[30] Anglers find spawning season to be a very successful time to fish for bluegills, as they aggressively attack anything, including a hook, that comes near.

In this manner, bluegills have been crossed with black crappie (Pomoxis nigromaculatus) and largemouth bass (Micropterus salmoides).

They are noted for seeking out underwater vegetation for cover; their natural diet consists largely of crickets, water bugs, larvae, and very small fish.

[40] The IGFA all tackle world record for the species stands at 2.15 kg (4 lb 12 oz) caught from Ketona lake in Alabama in 1950.

[43] Populations with large males are increasingly difficult to find, and are usually only found in remote locations without angling pressure[38] or in more southern regions where growth rates are high.

[44] In a 1973 study reported by the EPA, the waterborne administration of 180 ppm of calcium propionate was found to be slightly toxic to bluegill.