Resumo. Abstract Reservoirs play important roles in local socioeconomic development and are particularly relevant in developing countries. The rearing of Nile tilapia (Oreochromis niloticus) in cages is one of the fastest growing activities carried out in reservoirs since it is a strategy to sustain the growing demand for food fish. Most reservoirs are in eutrophic or hypereutrophic conditions in the semi-arid northeast region of Brazil and thus, the expansion of aquaculture endangers the ecological functions of the reservoirs by increasing the eutrophication potential. On the other hand, aquaculture contributes to economic development by generating jobs and income for the population and being an important alternative in the production sector for riverine populations. In this context, we present in this article our opinion about the sustainability of fish farming activities in net cages in reservoirs of the Brazilian semiarid, especially when subjected to extreme drought events.