During a survey made in 2004 and 2005 in Syrian fish farms of the Orontes valley and on natural water fishes harvested in the Orontes River and in Lake Assad (a water reservoir of the Euphrates River), 145 specimens of fish belonging to 15 fish species were examined for monogenean infections. Eleven monogenean species (8 Dactylogyrus spp., 1 Silurodiscoides sp. and 2 Cychlidogyrus spp.) were found in the gills. Monogeneans infecting farm-cultured fishes were the same as those commonly occurring in cyprinids (Dactylogyrus anchoratus, D. extensus, D. lamellatus) and filapia (Cychlidogyrus tilapiae, C. arthracan thus) cultured in Europe and in tropical countries. Among monogeneans found in fishes of natural waters, typical representatives of the Tigris-Euphrates Basin (Dactylogyrus carassobarbi, D. holciki) and species common in the Holoarctic zoogeographical zone (D. alatus, D. carpathicus, D. distinguendus and Silurodiscoides vistulensis) were equally found
