The male bluebreast darter has bright red spots on each side, red fins and a blue breast. The female has brown spots on her sides, brown fins and a white to light blue breast. The back is green to gray while the belly is white to light green. The second dorsal, caudal and anal fins have a black edge. There is a dark teardrop shape under the eye. This species can attain a maximum length of about three and one-fourth inches.
Adults of this species live near large boulders in fast riffles of clear streams at a depth between four and 11 inches. Young are found in the same sections of the streams but near smaller rocks in shallower water. This species feeds on small crustaceans and insects. The bluebreast darter is on the western edge of its range in Illinois, where it lives in the Middle Fork of the Vermilion River and in the Salt Fork of the Vermilion River. This river system is one of the best aquatic ecosystems in the state, but it has declined in quality mainly due to agricultural and urban runoff, and its fish populations are reduced in size as well. The bluebreast darter is listed as endangered in Illinois.