Phycocyanins are water-soluble proteins that work as accessory pigments and have several properties, such as immunostimulant action, cholesterol reducing effect, anti-inflammatory, antiviral, anticancer, antioxidant effects, among other uses. This study aimed to evaluate the accumulation of phycocyanin and biomass production of the microalgae Arthrospira (Spirulina) platensis grownin fish effluent. The experiment was carried out in two phases. The first developed in an indoor environment with controlled conditions, while the second, in a recirculation system, in an outdoor environment, using for both phases the Venkataraman media (control) and Nile tilapia effluent. There was no significant difference (p>0.05) between the performance of algae grown under the same conditions. Phycocyanin concentrations were higher for the treatments using modified Venkataraman medium. The purification process by ion exchange chromatography resulted in higher pigment concentrations for the eluted fractions with 0.2 M NaCl for all crude phycocyanin extracts.