This study was directed at the Atshan stream in Al-Samawah for the duration of the October 2020 till September 2021. The station (31°18'12.2"N 45°11'01.1"E). The aquatic factors included by this study has been recorded monthly from stations which include dissolved oxygen , water heat, pH , salinity. Fishes were taken by gill nets, electro-fishing, and hand network. A whole of 1055 fish were founded which included 12 species plus 7 families. 7 species from them are local species where as five of them are foreign species. The mainly abundant species was Oreochromis aureus (blue tilapia) established 33.2% of all caught, the second species is C. auratus represented 27.7% of caught fish and third species is Carasobarbus luteus (Himri) instituted 15.9%. It is noticeable that alien species prevailed in the Atshan river, they constituted 68.6% of total caught. This study considers the first fish assemblage in Atshan river