back and sides are pale olive or straw-colored and the belly whitish, two longitudinal rows of dark spots along either side and a single mid-dorsal row
uncommon but widespread inhabitant of the upper Mississippi River, the Thompson Fork of the Grand River and Chariton River in southcentral Iowa
aquatic insects and other small invertebrates
The trout-perch is an uncommon but widespread inhabitant of the upper Mississippi River, the Thompson Fork of the Grand River and Chariton River in southcentral Iowa. It also inhabits some of the natural lakes of Dickinson County and the Big Sioux River and its tributaries in northwest Iowa. This fish prefers stream habitats with high water quality and is most commonly found in streams that have deep pools and bottoms consisting of sand and gravel. Lake populations avoid mud-filled bays. Stream channelization has eliminated pool-type habitat in the original range and, coupled with increased turbidity and siltation, Iowa distribution probably has been reduced in recent times.
Trout-perch are thick-bodied, translucent-appearing fish. The mouth is horizontal and large with the upper jaw not reaching beyond the front of the eye. The tail fin is deeply forked and a fleshy adipose fin is present. The single dorsal fin has two weak spines and 10 to 11 rays. The anal fin has a single weak spine and 6 to 7 rays, and the pelvic fin one spine with 8 to 9 rays. A lateral line is present and contains 47 to 58 scales. The back and sides are pale olive or straw-colored and the belly whitish. There are two longitudinal rows of dark spots along either side and a single mid-dorsal row. Adults are commonly 3 to 5 inches in length.
In physical appearance this fish resembles both a trout and a perch. It has the adipose fin and naked head of the Salmonids but the ctenoid scales, fin spines, and mouth shape similar to Percids. The fish is nocturnally active in the shallows, foraging along the bottom for aquatic insects and other small invertebrates. During the daylight it moves into deep water or hides around structure. It spawns from May through August over rock and sandy bottom. They are random spawners, and no parental care is given to the eggs or fry. Females reach a larger size than males, and their life span is 4 to 5 years. The trout-perch is a major source of food for many game fish in our northern natural lakes.