With a growing world population and increasing demand for quality food in sufficient quantities, aquaculture fits in this context as active producer of high quality animal protein in large quantities by field use. The production of fish in farm ponds and has practiced for over five decades in Rio Grande do Sul, and the system is commonly used in carp polyculture, which consists of intercropping different species of carp to improve the performance of each one and therefore achieve greater productivity. But the carp polyculture currently used has a low technological level, the production obtained is considered small. Studies have been performed by adding the silver catfish, the traditional polyculture, thus obtaining good results. Some studies were performed on economic viability, but with a single species, or consortium, as is the case of polyculture of shrimp and Nile tilapia. This study tested the polyculture with partial subtituição 25%, 50% and 75% of silver catfish and carp by Nile tilapia. The economic viability of all polycultures studied were analyzed under the condition of certainty by obtaining the Net Present Value (NPV), Annual Value (AV), Internal Rate of Return (IRR) and Payback. It was concluded that replacing 25% of silver catfish and carp by Nile tilapia has higher biomass production and that an investment in polyculture with vita useful 25 years is economically feasible for a fee Minimum Attractiveness (TMA) of 6.17%.