The effect of Spirulina supplementation on reduction of copper toxicity based on food utilization, phosphatases activities and selected haematological parameters was studied in a freshwater cultivable fish C. mrigala. Metal concentration in medium, body tissues and fecal matter was also analysed. Sublethal exposure of C. mrigala fed Spirulina-free diet significantly reduced the consumption and growth rates, phosphatases activities and haematological parameters. However, the above parameters enhanced in the copper exposed fish fed with Spirulina supplemented diets. A significant positive correlation was obtained for the relationship between supplementation of dietary Spirulina and copper defecation through feces. Among the doses of Spirulina supplementation, 6% addition has been considered optimum for C. mrigala since this dose produces maximum elimination of copper from the body and feces and better improvement on growth, phosphatases activities and haematological parameters.