Fish Pathology
Online ISSN : 1881-7335
Print ISSN : 0388-788X
ISSN-L : 0388-788X
Short Communications
An Outbreak of Neoergasilus japonicus (Copepoda: Ergasilidae) on the Japanese Rice Fish Oryzias latipes Reared in an Outdoor Tank
Hirotaka KatahiraOrie IkedaTaiga Yodo
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2023 Volume 58 Issue 4 Pages 171-174


An outbreak of ectoparasitic copepods occurred on the Japanese rice fish Oryzias latipes stocked in an outdoor tank for the extraterritorial conservation program. ​Only the adult female copepods were found on the skin and fins of the host fish. ​The parasite was identified as Neoergasilus japonicus from the morphological characters including an inflated projection on the second segment of the exopod of the first swimming leg, and the single-segmented exopod and endopod of the fourth leg. ​Partial sequence of 28S rDNA and cox1 genes also supported the morphological identification. ​This is a new host record for N. japonicus. ​A bath treatment with 1% salt concentration was effective in detaching the parasite within a day.

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© 2023 The Japanese Society of Fish Pathology
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