rilapiazlUiii fish were exposed to aluminum chloride under alkaline water (pH 7.3). The fish were divided into 4 groups control group and three groups exposed to 50, 100 and 200/ig / liter of aluminum chloride respectively for 24 hr., 48 hr. and 96 hr.The fish showed a physiological response after 24 hr. of exposure to 50, 100 and 200ug / liter of aluminum chloride respectively where, approximately 100% increase in red blood cells (RBCs), white blood cells (WBCs), liematocrit value (He) and hemoglobin content (Hb) respectively, Also, there are increased in serum glucose level, total protein, aspartate and alanine amino transferase activities (AST and ALT) and increased serum creatinine and uric acid concentration after 24hr. from exposure the fish to 50, 100 and 200pg / liter of aluminum chloride respectively. The results indicate that the fish that exposed to 50, 100 and 20Qug / liter of aluminum chloride respectively for 48 hr. increase blood constituents, serum glucose level, serum total protein and serum AST, ALT activities, creatinine and uric acid level. Moreover, the fish that exposed to 50, 100 and 20Qug / liter of aluminum chloride respectively for 96 hr, showed highly significant increase of RBCs, WBCs, He and Hb as well as in the serum glucose level, serum total protein and serum AST and ALT activities. The serum creatinine and uric acid showed increased in the fish that exposed to 50, 100 and 200ug / liter of aluminum chloride respectively for 96 hr. These data suggest that fish respond to aluminum exposure by increasing their WBCs, enzymes of liver functions and kidney functions.