• Korean Journal of Ichthyology
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• v.17 no.1
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• pp.1-7
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• 2005

A new chub, Zacco koreanus sp. nov., is described on the basis of 104 specimens from six localities in Korea. The new species is distinguished from other Zacco species by the following characteristics: 9~10 scales above lateral line to dorsal fin origin, yellowish anterolateral side of body, no hemicircular red blotch on the upper margin of the eyes, reddish anterior margin of pectoral fin, larger orbit diameter and narrow interorbital width. The new species is widely distributed in the most streams of Korea, except the Yeongsan R., while Zacco temminckii is restricted in the Dongjin R., Yeongsan R., Seomjin R., Tamjin R. and Nakdong R. in Korea. When the two species occurred sympatrically in the same stream, Z. koreanus sp. nov. prefered mostly rapid lotic environments while Z. temminckii inhabited lentic ones. The Korean Z. temminckii was redescribed herein. A key to the Zacco species of Korea and Japan is provided.