Electrophoretic analyses of liver and muscle ofChanna punctatus revealed that they contain atleast six and eight fractions of esterase, respectively. Characterization of esterase was made on the basis of their responses towards certain inhibitors. Liver esterase consists of acetylesterase and carboxyl esterases, whereas the muscle esterase has three types namely acetylesterase, carboxylesterase and cholinesterase. The liver and muscle ofC. Punctatus subjected to maximum sublethal concentration of carbaryl were electrophoretically analysed and it was found that both liver and muscle showed only three fractions of esterase.