Sawa Lake is an abnormal lake in Iraq. It was characterized by the high degree of salinity among the Iraqi marshes. It is a euhyline water body of no inflow and outflow. The lake is an elongated closed basin with no channel of surface water available to it. The results of the present study are showed three types of fauna, the biggest numbers of fauna belong to Ostracods. The other fauna are represented in type of algae (Charophyta) and one genus of Gastropods. The SEM analysis indicated that the organisms are affected with water lake chemistry, the element S exists in the wall of Charophyta and Ostracoda, while the gastropods does not contain this element. They concluded that these organisms were affected with the salinity except gastropods genus which transport by bird feet from Caspian Sea. There are many fauna that occurred in Sawa Lake, these are reflect of fresh water sources enter to the lake.