In experiment period, nine parasitic species (Trichodina siluri, Trichodina pediculus, Trichodina centrostrigata, Trichodina heterodentata, Trichodina mutabilis, Trichodina compacta, Triparliella clavodonta, Tripartiella bulbosa and Paratrichodina incisa) belonging to three genera (Trichodina, Tripartiella and Paratrichodina) were found on two hundred and sixty examinedfishes. The infection rate and intensity of parasites on skin and gills of fish in turn were 34.5 percent and 2 - 29 parasites/field of vision, respectively. In treatment test, the result showed that Trichodina, Tripartiella and Paratrichodina parasitized on fish were eliminated absolutely after soak treatment of CuSO4 between 0.5 and 0.7 ppm for 24 hours.