EN
Twenty-three Alburnoides bipunctatus originating from three natural environments were examined. The following species of Monogenea were found and described: Gyrodactylus gracilihamatus Malmberg, 1964; G. hronosus Žitňan, 1964; G. alburnoidesi Chiriac, 1969; G. euzeti sp. n.; Gyrodactylus sp.; Octomacrum europaeum Roman et Bychovsky, 1956; and Paradiplozoon alburni Khotenovsky, 1982. All the species are noted for the first time in Poland. The differential diagnosis of G. euzeti sp. n. was performed on the basis of the comparison with G. laevis Malmberg, 1956 the species most similar to it a parasite of Phoxinus phoxinus.