During a parasite examination of 31 fish species from 16 families, collected from three different stations in the Shatt al-Arab River between September 2023 and June 2024, 13 parasite species were identified. These included one protozoan (Ichthyophonus sp.) found in the internal organs of three fish species from two families, and six species of Myxozoa (from four genera). Chloromyxum and Ellipsomyxa were found in the kidneys and spleen, respectively, of Planiliza subviridis. Myxobolus was observed in the spleen, gill filaments, and intestinal walls of P. subviridis, while Hennegoides was found in the kidneys of Acanthopagrus sheim. Four trematode species were also recorded: Erilepturus hamati from the intestines of seven fish species across four families; Fastuala basiri Hafeezullah & Siddiqi, 1970; F. gangetica (Srivastava, 1935); and Aphanurus sp., all from the intestines of Tenualosa ilisha (the latter may be new to science). Hysterothylacium sp < em>. type BC larvae were recorded in the intestines of two fish species, and Echinocephalus sp. type BB larvae were found in five fish species. The acanthocephalan Neoechinorhynchus dimorphospinosus Amin & Sey, 1996 was found in the intestines of two mullet species (P. klunzingeri and P. subviridis). A total of 14 marine fish species were found to be free of endoparasitic infections. The six myxozoan species and the trematode Aphanurus sp < em>. were recorded for the first time in Iraq and the Arab Gulf. Additionally, 17 new host records were included in the study across four different fish hosts.