摘要:This study was conducted to assess the histo-pathological changes in liver and intestine and sero-hepatic biochemical response of Oreochromis mos-sambicus induced by nano CuO during 96-hrs of LC50 Assessment. The trial was conducted at fish laboratory of Government College University Fai-salabad Pakistan. The experimental fish (n=60, weight approx.5 grams)were divided into 6 aquari-ums (n=10 per aquarium).Each group was treated with different concentrations of nano CuO as A (0.00).B(0.8),C(1.00),D(1.20).E(1.60),and F (2.4)mg/L. The fish were observed for physical symptoms appear during 96 hours and dead fish was immediately dissected after mortality to collect liver and intestine for histological analysis. Serum was also collected from each fish before mortality to as-sess the hepato-biochemical changes. Alive fish re-mained after 96 hrs were dissected to proceed further analysis. This study approach was not previously re-ported in five-year literature especially for the as-sessment of LCso of Oreochromis mossambicus and initial physiological changes to experiment with fur-ther studies.