This paper presents a water quality monitoring system using low power hardware based in the Internet of Things. Six sensor nodes for water quality monitoring in pisciculture are installed in three region of the Peruvian amazon. The sensor node is a modular hardware composed by control, communication and sensor module that measure parameters such as pH, conductivity and temperature. All data information is managed by software platform designed using open source tools, data information allows to control water pollution and their effect in the pisciculture. Data acquired is used by the researchers of the Instituto de Investigaciones de la Amazonía Peruana to study the health and growing population of paiche fish.