## 2 Related Work  
In this section, the state of art of the systems for fish farm monitoring is shown. Several authors propose different systems for water quality monitoring. Water quality monitoring and fish behavior monitoring are crucial to improve the efficiency of aquaculture. In this section, the related work on the available water quality monitoring systems and some of the research performed on fish behavior monitoring is presented. Wireless Sensor Networks (WSN) have become a solution for performing water quality monitoring. [PERSON] et al. presented in [12] a WSN-based water monitoring system. The system employed ZigBee to transmit the information gathered by the sensors from the recirculating system. Then, the information was stored in a MySql database. Temperature, pressure, and dissolved oxygen was measured throughout the day. When a problem was detected, an SMS or an E-mail was forwarded to alert the person responsible for the facility. Another WSN-based water monitoring system was presented by [PERSON] et al. in [13]. The system was able to measure pH, water temperature, water level and dissolved oxygen. The data was forwarded to a database that provided the information to the software to be monitored in real-time. The software was developed employing Visual studio 2005 and separates logic, display and data layers to improve scalability and reusability. Lastly, warnings were forwarded via SMS or graphical device twinkle to the users. WSN is employed as well for the recirculating monitoring system proposed by [PERSON] et al. in [14]. The system was composed of a three-layer architecture comprised of the remote layer, the server layer and the client layer that obtained, transported, and displayed the information gathered on water temperature, conductivity, salinity, and pH. Moreover, a software solution was developed as well to monitor the obtained information by accessing a Postgre SQL server employing a WLAN (Wireless Local Area Network). [PERSON] et al. presented in [15], a WSN-based water quality monitoring system that gathered data on pH, water temperature and dissolved oxygen. A real-time interface allowed the display of the data numerically and graphically. Several testing results were provided displaying fluctuations during the day. These results show a 1.40% of relative error for pH, 0.27% for temperature and 1.69% for dissolved oxygen. The water quality monitoring system presented by [PERSON] et al. in [16] measured pH, water level, water temperature, and dissolved oxygen and employed ZigBee to forward the data. They used the LabView software (National Instruments Corporation, Austin, TX, USA) to display the obtained information. Furthermore, several experiments regarding communication performance, battery performance and sensor readings were performed over a period of six months. Results showed the fluctuations of these parameters throughout the day. [PERSON] et al. designed in [17] a water quality monitoring system for fish farms. It employed artificial neural networks (ANN) to forecast water quality to prevent losses. The data acquisition node measured water and room temperature, percentage of dissolved oxygen saturation, dissolved oxygen concentration, pH, electrical conductivity, and salinity employing a variety of sensors. The data was then forwarded to a server to be remotely accessed. [PERSON] et al. proposed in [18] an IoT-based water monitoring system for aquaculture. They employed an Atlas Ph Probe digital sensor (Atlas Scientific, Long Island City, NY, USA), an analog temperature sensor and an Atlas Dissolved Oxygen Probe as well as an Arduino node that employed a ZigBee module to forward the information to a MySQL database. Moreover, the system utilized 200 mA/h rechargeable batteries and was able to perform for 8 h. The information was able to be visualized through a desktop or a mobile application. [PERSON] et al. designed in [19] an environment monitoring system specific to aquaculture farms. They measured water quality, fish food and the medication provided to the fish.