This study was designed to evaluate the physiological and cytological responses in liver of GIFT tilapia (Oreochromis niloticus) to acute copper exposure. Fish were exposed to three Cu treatments at the following concentrations: 0 (control), 1.96 mg/L and 3.92 mg/L, and liver samples were collected after 96h of exposure. Observation of oil red O staining showed that acute copper exposure increased lipid accumulation in liver, which may due to changes of hepatic enzyme activities (malic enzyme, lipoprotein lipase, hepatic lipase, fatty acid synt...