The redear sunfish shares several similarities with the bluegill but stands out due to its unique coloration and slightly larger size. It exhibits faint vertical bars that travel downwards from its dorsal fin. While it has a dark-colored dorsum, its ventral side is yellow-green. The males feature a distinctive cherry-red edge on their operculum, while females display orange coloration in the same area. On average, adult redear sunfish measure between 20 and 24 cm (7.9 and 9.4 in) in length, with a maximum length of 43.2 cm (17.0 in), surpassing the bluegill's maximum length of about 40 cm (16 in). Additionally, redear sunfish tend to be larger in weight, averaging about 0.45 kg (0.99 lb), compared to the average bluegill weight.
Native to the southeastern United States, redear sunfish are primarily found in warm, quiet waters of lakes, ponds, streams, and reservoirs. Their natural range extends from North Carolina to Florida, west to southern Illinois and Missouri, and south to the Rio Grande drainage in Texas. However, due to their popularity as a sport fish, they have been widely introduced to various locations across North America. In their natural habitat, redear sunfish prefer areas with logs, vegetation, and freshwater marsh wetlands, where they often congregate in groups.
The redear sunfish is renowned for its diet of mollusks and snails, which led to its popular nickname, "shellcracker." These fish skillfully maneuver along lakebeds, searching for and cracking open snails and other shelled creatures. Large L. microlophus individuals predominantly focus on hard-shelled prey such as ostracods, hydrobiid snails, and mussels throughout the year. Smaller fish exhibit a more diverse diet, including zooplankton, amphipods, chironomid and ceratopongonid larvae, and cladocerans, with variations depending on the season. Apart from snails, redear sunfish also consume algae, aquatic worms, copepods, midge larvae, ephemeropteran and odonata nymphs, crayfish, small fish, and fish eggs. Their specialized pharyngeal teeth allow them to crunch exoskeletons and even open small clams. Notably, their ability to feed on quagga mussels, an invasive species, has made them valuable for controlling their population in freshwater ecosystems.
During the spawning season, male redear sunfish gather and create nests in close proximity to one another, forming colonies. Females then visit these nests to lay their eggs. It's worth mentioning that the redear sunfish sometimes hybridizes with other species of sunfish, further contributing to the diversity within the Centrarchidae family.
The redear sunfish holds great evolutionary significance as it is the first-known species within the Centrarchidae family based on fossil records. Fossils dating back to the Middle Miocene, approximately 16.3 million years ago, have been discovered, shedding light on the early history of this remarkable fish.
Recreational anglers widely recognize redear sunfish as a popular panfish. Its reputation as a feisty gamefish, coupled with its delectable taste, makes it a sought-after catch. In fact, the International Game Fish Association (IGFA) all-tackle world record for the species stands at an impressive 2.61 kg (5 lb 12 oz), caught in 2014 from Lake Havasu in Arizona. Fishing enthusiasts appreciate the challenge and excitement of pursuing this species, contributing to its enduring popularity.