A combined aquaculture-algae system was developed for the purification andreuse of effluent water from intensive fish production in a combination of a high-rate algalpond and extensive fishpond. The integrated system was operated as a closed system, thusthe water demand was reduced through the recirculation of the treated water. The pilot-scale experimental system consisted of three different compartments: tanks for intensivefish production, an algal pond where the excess nutrients are removed by algae uptake anda fishpond where the produced algae biomass was consumed by fish. The objective of thisstudy was to describe and evaluate the nutrient transformation efficiency of the combinedsystem through the analysis of the organic carbon, nitrogen and phosphorus budgets.