The current investigation aim was to study the hematological and serum biochemical changes under sublethal calcium zincate nanoparticle (CaZnO₂ NP) concentration in the fresh water fish Cyprinus carpio. Fish were exposed to two sublethal concentrations 3.53 and 7.05ppm of CaZnO₂ NP for 7, 14 and 21 days. Simultaneously control was maintained without nanoparticle. Fish were sampled at the end of each interval to measure the hematology and biochemical variables such as red blood cells (RBC), white blood cells (WBC), hemoglobin (Hb), glucose, total protein (TP), cholesterol, creatinine, alanine aminotransferase (ALT/GPT) and aspartate aminotransferase (AST/GOT). From the results it is inferred that CaZnO₂ NPs affect the hematology and biochemical parameters of fish Cyprinus carpio.