In this study, parasites of the following Fish species were investigated in Lake Manyas (Kuş) from January-1997 to November-1998. At the end of this research, (Dactylogyrus chalcalburni, Monogenea) were found on the gills of Chalcalburnus chalcoides. During the study, in 118 fish specimens of C. chalcoides was investigated and total of 232 Dactylogyrus chalcalburni was recorded from fish. Morphologic, anatomic and characteristic structure of the parasite species were described using figures. In addition to, infection density of the parasites were analysed using seasonal and fish size distribution result for the fish. During the research, Dactylogyrus chalcalburni number was sharply increased in autumn and, the parasite specimens appeared in low number as a less community in summer.