The potential toxicity of dyes produces enzymatic changes in metabolic tissues due to alteration in metabolic pathways in these animals. Muscle tissue of fish was analysed for the effects of methyl red, since it is a major target tissue involved in key metabolic activity and form the edible part of the fish. The present study unravels the activity of enzymes involved in muscle oxidative metabolism in fishes exposed to methyl red dye. The fishes were maintained for a period of 40 days at one- fifth sub lethal concentration. The present study revealed no significant change in hexokinase activity, an increased activity in lactate dehydrogenase and (LDH), a decline in activity of succinate dehydrogenase (SDH) and an increase in activity of malate dehydrogenase (MDH).
