Abstract: Water used in domestic and industrial application can become polluted to varying degrees. The dairy industry is an important part of the overall food industry which contributes materially to fluid wastes. Hence an investigation had been carried out to study the physico chemical parameters of dairy effluent and its effect on biochemical constituents present in different organs of fish, blue gourami (Trichogaster trichopterus). The results of analysis of physicochemical parameters revealed that industry treated dairy effluent was greyish black in colour with disagreeable odour. pH was alkaline with low organic load such as EC, TSS, TDS, BOD and COD, indicating high pollution potential of the effluent. The results of impact of industry treated dairy effluent on biochemical constituents present in different organs of fish, blue gourami showed that among the different organs of fish such as gills, liver and muscle studied for biochemical estimation, gills was most affected organ which showed decreased amount of biochemical constituents than that of liver and muscle of fish and also carbohydrates was decreased drastically than lipid and protein.