The Warmouth (Lepomis gulosus) is a species of freshwater fish. It is a member of the sunfish family (family Centrarchidae) of order Perciformes. It is native to a wide area of the United States, from Minnesota to western Pennsylvania in the north and from the Rio Grande in New Mexico east to the Atlantic in the south, inhabiting the heavily vegetated, muddy-bottomed habitats typical of the sunfishes.

The warmouth’s specific epithet, gulosus, derives from the Latin gulōsus (gluttonous). The origin of the common name “warmouth” is due to the stripes around the mouth of the fish bearing a resemblance to warpaint.

Besides their distinctive spotted patterns, warmouths can be easily identified and distinguished from other panfish or sunfish by their proportionally large mouths. Other panfish of the same weight will have mouths 2-3 times smaller than that of the warmouth, whose oral proportions are in line with those of Largemouth/Black bass. It is often stated that warmouths have the body of a brim (a small common sunfish) and the head of a bass, leading to rumors that it is a man-made crossbreed.

Warmouths are also rumored to be very aggressive, and will strike at lures and baits even after being released by anglers moments before.