The ornamental ?¯?¬?sh, Koi carp fingerlings were exposed to sub-lethal concentrations (1/5th of 96 h LC50) of Malathion (7.2 mg/l) and Glyphosate (13.2 mg/l) along with control group for a period of 30 days. Alkaline Phosphatase (ALP), Lactate Dehydrogenase (LDH), Aspartate aminotranferase (AST), Alanine aminotransferase (ALT) and Acetylcholinesterase (AChE) were assayed in different tissues at the end of 15th and 30th day. The results infer that, AChE shows strong significant (P<0.05) inhibition in gills than that of muscle in both treatments at the end of the 30th day. Whereas ALP activity in brain, gills and muscle of fish shows fluctuation between the treatment groups, while on the other hand ALT, AST and LDH levels were significantly declined in all the tissues (P<0.05) when compared to control. Enzymological alterations observed in the present study indicated the fact that Malathion and Glyphosate are toxic to Koi carp fingerlings at the tested concentrations. Therefore, the findings of the present investigation could be considered as possible biomonitoring tool for the assessment of pesticide contaminations in aquatic ecosystem
