Catla catla, a fresh water edible carp fish, the fingerlings, when exposed to different sublethal concentrations of chromium for a different periods1, 8, 16, 32 days of time brought changes in the structure and morphology of the nonosmatic organs such as muscle. The severe destruction of muscle tissue in the fish was evident by the splitting in the muscle fibers, karyolysis, nuclei exploitation atrophy, hypertrophy, hemorrhagic condition and ultimate wavy appearance of muscle fibers suggest significant concentration of metal accumulation in this effector target organ. All the changes which take place affect the contractile ability of the muscle fibers.