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The longnose dace (''Rhinichthys cataractae'') is a freshwater minnow native to North America. ''Rhinicthys'' means snout fish (reference to the long snout) and ''catarace'' means of the cataract (first taken from Niagara Falls). Longnose dace are small, typically less than 100 mm and characterized by their fleshy snout that protrudes past the mouth. They are well adapted for living on the bottom of fast-flowing streams among stones. Longnose dace eat algae and aquatic insects and are important forage minnows for larger predatory fish. ==Description== Longnose dace can be mistaken for suckers because of their subterminal "sucker-like" mouth. However, longnose dace (like all members of the cyprinidae family) lack small fleshy projections, called papillae, on their mouths. Juveniles have a black lateral line that extends from the beginning of the eye to the caudal fin that fades as the fish matures. The lateral line in juveniles is not present in all populations. In adults, the dorsal side is dark green to black, the lateral side is darkish to silvery with mottling often present, and the ventral side is pearly. Both adult males and females may have bright orange-reddish colouration at the base of pectoral, pelvic, and anal fins and on the upper lip. This colouration is typically associated with breeding males in the subspecies ''Rhinichthys catarace catarace'',〔Bartnik, V.G. 1971. "Comparison of the breeding habits of two subspecies of longnose dace, ''Rhinichthys catarace''". Canadian Journal of Zoology 50: 83-86.〕 but the validity of this subspecies has yet to be confirmed. Museum specimens of females also show intense orange-reddish colouration at the base of the fins and upper lip,〔Nelson, J.S. and M.J. Paetz. 1992. The Fishes of Alberta. The University of Alberta Press. Edmonton, Alberta.〕 therefore colouration is not an accurate predictor of sex. The maximum length of longnose dace is 170 mm, but they are usually less than 100 mm. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「longnose dace」の詳細全文を読む スポンサード リンク
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