• Family: Centrarchidae (Sunfishes)
• Other Names: Stumpknoker
• Ohio Status: Sport fish
• Adult Size: Typically 6-8 inches, can reach over 11 inches. Usually weighs less than 1 pound, can reach 1.5 pounds.
• Typical Foods: Crayfish, large aquatic insect larvae, and small fish.
Warmouth sunfish are not as deep bodied as bluegill or redear sunfishes but are deeper bodied than largemouth or smallmouth bass. They can change from light to dark brown very quickly to blend in with their surroundings. They have large dark blotches on their sides and back which do not normally form an organized pattern. Younger fish can sometimes have a purplish sheen to their sides. Warmouth sunfish also have a very large mouth and red eyes. They have alternating dark and light lines on the side of their cheek radiating away from the eye that extend to the rear of the gill cover. These lines are not blue or green like those of green, longear, or pumpkinseed sunfishes. Warmouth sunfish also have a light colored margin to the fins that can be white, orange, yellow, or red. The rock bass is similar in appearance but has 6 anal fin spines compared to the 3 that a warmouth sunfish has. Rock bass have a teardrop under the eye, no radiating lines on the cheek, and a black margin to the fins. Breeding male warmouth sunfish have gold or light blue speckles on their sides and a faint red spot at the rear base of the dorsal fin.
Habitat and Habits
Warmouth sunfish are typically found in clear shallow waters with dense rooted aquatic vegetation. This habitat is most often found in natural lakes, sluggish streams, oxbows, and marshes. They are a secretive fish hiding in cover such as stumps, brush, or vegetation. They are also found in some of Ohio's reservoirs that have relatively clear waters and abundant aquatic vegetation. They are most common in north east Ohio in lakes such as the Portage lakes and Mogadore reservoir. They are found throughout most of the rest of the state as well, but generally are less common than in northeast Ohio. The exception to this is they are almost entirely absent in northwest Ohio except for Nettle lake in Williams County. The similar looking rockbass is rarely found living in the same habitat as the warmouth sunfish.
Reproduction and Care of the Young
Warmouth sunfish do not spawn in colonies like other sunfish species. However, males do fan out a nest, usually near a rock, stump, clump of vegetation, or other large object. Spawning occurs from May though July. The male guards the eggs and young until they disperse from the nest. During this time, like other sunfish species, the male will chase intruders off with gill covers spread wide and mouth open, to make himself appear larger.