They primarily feed of dipteran larvae and other aquatic insects. Small crustaceans, such as copepods, clasocerans, and ostracods are also a part of their diet. The only terrestrial insect they eat are ants. Longnose shiners also eat various plant materials, such as seeds of various sedges, diatoms, desmids, filamentous algae, and aquatic fungi. With increasing size, longnose shiners can have a more diverse diet, and have been found include mayfly larvae in their diets. The longnose shiner is a benthic, schooling species found most often in moderate current over clean sand or small gravel substrata in medium to large streams. Their habitats are often described as shallow (depths to ca. 60 cm), clean, white, open, sand areas along the edges of sand bars in low to moderate flow. Though they are most abundant near the lower end of sand bars and shoal, where there is a reduced current flow, they are also commonly found in areas where stream banks are covered with woody or brushy vegetation. Longnose shiners have also been found to colonize disturbed areas around bridge repair sites where the operation of heavy machinery has created a shallow, sand-bottom stream channel. The sex ratio of longnose shiners is about 1:1, and both sexes mature at about the same size (30 mm) The average size of males are about 34.9 mm long and females are about 33.8 mm long. The average size of females tends to vary in different drainage systems. Larger females usually produce larger ova, with mature ova diameters averaging from 0.84-0.95 mm. Variances in female size and average diameters of mature ova seem to be strongly correlated with the amount of surface runoff in the area. The breading season of longnose shiners typically lasts from March until October, in waters of about 17-29˚ C. Longnose shiners generally produce multiple clutches during a breeding season. There may be two breeding peaks, one at the very beginning of the season and then another in the middle of the season, around July. Females average from 62-121 mature ova per clutch and usually produce anywhere from 15-129 eggs. Longnose shiners do not prepare the substrate for a spawning event, and instead practice broadcast spawning, in which they scatter the eggs and sperm. This type of reproduction results in a lack of parental care to both egg and larvae.