The current study conducted at Al-Dalmaj marsh (20km north of Afaq district-Al-Diwaniyah province/ middle of Iraq),for the period from first November 2021 - end of May 2022, The study aimed to isolation and identification of external and internal parasites on some common fish species in the Al-Dalamaj Marsh region, A total of 345 specimens of fish were collected, this fish were belonging to three families, including Cichlidae, Mugilidae and Cyprinidae,were including Cyprinus carpio (120 specimens) Coptodon zillii (100 specimens) and Planiliza abu (125 specimens). The study showed that the three species were infected with 29 species of internal and external parasites, it included four species of Ciliophora, twenty species of Monogenea, one species of Cestoda, two species of Acanthocephala and two species of crustaceans. C.zilii was highly infection (43%) followed by P.abu (42.4%) and lowest infection was in C.carpio (37.5%). It was observed that the Cyprinus carpio was infected with 15 species of parasites,followed by Planiliza abu,which was infected with 10 species, while Captodon zillii was infected with only 8 species of parasites. Eleven new hosts for some registered parasites in this study were recorded for the first time in Iraq, nine of them Belong to Monogeanea, One species of Cestoda and one species of Ciliophora. The detected new species were four species in Cyprinus carpio (Gyrodactylus cotti, G.rarus, Khawia rossittensis and Cichlidogyrus sclerorus). Four species in Planliza abu (Dactylogyrus lenkoranoides,Gyrodactylus barbi, G. vimbi and Paradiplozoon homoion), and three species in Coptodon zillii (Trichodina gracilis, Microcotyle donavani and Diplozoon spp.).