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Minnows are fishes belonging to the family Cyprinidae, which includes daces, chubs, shiners, cutlips, stonerollers, carp, and goldfish. Native minnows are soft-rayed fishes, but carp and goldfish have ossified first dorsal and anal rays. Minnows have toothless jaws, but bear 1-3 rows of teeth on morphologically specialized fifth gill arches. Scales are cycloid, the head is scaleless, there are 19 principal caudal rays, and in native American forms the dorsal and anal fins are short. This is one of the two most speciose families of vertebrate animals, with more than 1500 species. They occur in fresh waters in Eurasia, North America, and Africa, but are absent from South America. The family is most diverse in China and southeast Asia. Of the fish families occurring in the Great Lakes region, the Cyprinidae is the most numerous in species and individuals. Minnows occur in lakes, ponds, streams, and reservoirs. Individual species often have restricted habitats. Certain forms inhabit only inland lakes; some are found only over sandy substrate; most species have preferred habitats in streams. Minnows exhibit a variety of spawning habits. For example, bluntnose minnow and relatives make nests on the underside of stones or wood, and the male guards the eggs. Spotfin shiners spawn adhesive eggs onto vertical surfaces. Creek chubs and common shiners bury the eggs in gravel and guard the nest but mainly to attract mates. Stonerollers gather gravel into mounds for nests. Male and female carp broadcast eggs upon the vegetation or bottom, then desert them. Some minnows, such as the redfin shiner, use nests constructed by other species. Most native Great Lakes minnows live 2-4 years and are less than 7 inches long, but fall fish reach 18 inches and creek chubs reach 1 foot. The introduced carp lives for decades and reaches more than 30 pounds. Because of their abundance, minnows are often the dominant biomass in the food chains of lakes and streams. Students generally find minnows to be the most difficult fishes to identify. The morphological differences between species are subtle, compared to other fishes in the Great Lakes. Also, the fish are small and bright colors are restricted to males in the breeding season. Most of our species and the most similar species are among shiners related to the genus Notropis. Convergence is common among these species, requiring special care in identification.
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