Cassava Sago industry is between the major water consuming and less polluting industries in India. In Tamil Nadu (State of India) in and around the city of Salem alone there are over 800 Sago factories are located. It is an agro-based industry, which let out lot of its wastewater into the nearby areas. Most of the factories are located near the banks of rivers and lakes and it has become customary to discharge the effluents to the rivers or lakes. It is noted as one of the significant contributors to water pollution by discharging its effluent.These effluents pose a serious threat to the environment and quality of life in the rural areas. Though numerous studies have been carried out to study the effect of different industrial effluent on fish the work on the effects of sago industry effluent on fish is totally wanting. The present study addresses the effect of sago effluent on the physiological, biochemical, histological, haematological responses of the Indian catfish Clarias batrachus.