Spirulina is an aquatic algae in fresh water; it promotes the growth and biochemical compositions of the animals. Paper and pulp mill effluent affect the aquatic life of flora and fauna Oreochromis mossambicusis test animals in between the length of 5-10 cm were selected for the study.Test animal exposed to lethal concentration of effluent to the fish in 96 hours and various sub lethal concentrations were prepared as follows 0.5%, 1.0%, 1.5%, 2.0% and 2.5% in 30 days of duration. In the duration, the test animal was tested in the morphometric parameters such as weight, total length, standard length, head length, snout length and length of caudal peduncle and biochemical parameters such as amino acids, protein, carbohydrate, glucose and lipids; in between the interval of 10 days up to 30 days.Next the 30 days, the fishes are reared in the same sub lethal concentration with standard food and Spirulina feed. During these experimental days, the same biochemical constitutions were tested.In the experimental days, in first 30 days the biochemical values are reduced, and in the recovery period the reduced values were regained.