Introduction. Pisciculture is an important activity to satisfy the alimentary necessities of a growing population. Therefore, it is necessary to develop environmentally responsible techniques. Cultivation based on periphyton is attractive, because it can feed the fish and improve the quality of the water, allowing a more efficient and cleaner system. Objective. To evaluate the effect of periphyton on some of the quality parameters of the water used for the cultivation of Nile-bocachico tilapia fish. Methodology. An experiment was performed during eight months in eighteen 90 m2 ponds with 2.7 tilapia fish per square meter and 0.7 bocachicos per square meter, with no fertilization. As a periphyton substract, vertical plastic pipes were installed (3.3 pipes/m2) and their presence or absence was an evaluated factor. Additionally, Articulo original / Original article / Artigo original