The study was conducted in the Shatt al-Basra Canal, with two stations selected for sampling from January 2023 to December 2023. The first station was located near the Mohammed Al-Qasim Bridge, while the second station was in the Al-Khuwaisat area, downstream. Samples were monthly collected. A total of 5,673 fishes were collected, including 45 species belonging to 30 families, with 40 marine species, one endemic species, and four invasive species. The Dorosomatidae family was dominated, with seven resident species, three seasonal species, and 42 rare species. The species Thryssa whiteheadi, Planiliza subviridis, and Coptodon zillii made up 46.5% of the total catch. Physical and chemical parameters measured during the study included water temperature (16-35°C), dissolved oxygen (5-9 mg/L), pH (7.1-8.15), light transmittance (18-71 cm), and salinity (20.2-47 ppt). The diversity index (H) values ranged between 0.31 and 1.57 at the study stations.