Abstract / Introduction / Summary:
Two adult females of Lernaea cyprinacea Linnaeus, 1758 were collected each from two individuals of medaka, Oryzias latipes (Temminck and Schlegel, 1846) (Beloniformes: Adrianichthyidae), in an artificial small pond at the Museum of Natural and Environmental History, Shizuoka, in Shizuoka Prefecture, central Japan. Each copepod was found to insert its anterior body into the host’s left eye or near the base of the right pectoral fin. In the former infection, the copepod induced exophthalmos (pop-eye). Peritrich ciliates were attached to the trunk and egg sacs of the copepods.