# Smart Low-Cost Control System for Fish Farm Facilities  
[PERSON]  
1 Instituto de Investigacion Para la Gestion Integrada de Zonas Costeras, Universitat Politecnica de Valencia, Carretera Nazaret-Oliva, s/n, 46730 Gandia, Spain; [EMAIL_ADDRESS] (L.P.); [EMAIL_ADDRESS] (S.S.) 1  
[PERSON]  
1 Instituto de Investigacion Para la Gestion Integrada de Zonas Costeras, Universitat Politecnica de Valencia, Carretera Nazaret-Oliva, s/n, 46730 Gandia, Spain; [EMAIL_ADDRESS] (L.P.); [EMAIL_ADDRESS] (S.S.) 1  
[PERSON]  
2 Department of Information and Communications Technologies, Universidad Politecnica de Cartagena, Plaza del Hospital, 2, 30202 Cartagena, Spain; [EMAIL_ADDRESS] 2  
[PERSON]  
1 Instituto de Investigacion Para la Gestion Integrada de Zonas Costeras, Universitat Politecnica de Valencia, Carretera Nazaret-Oliva, s/n, 46730 Gandia, Spain; [EMAIL_ADDRESS] (L.P.); [EMAIL_ADDRESS] (S.S.) 1  
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appearance of visible white spots. However, other diseases may go unnoticed and cause the chronic death of the fish. As a solution, monitoring both the external state of the fish and its behavior helps to prevent losses by providing the information to take all measures necessary. Therefore, the deployment of sensors, such as cameras, with the addition of data processing algorithms, can detect skin problems, parasites, fungus, cloudy eyes, swimming speed, or trajectory, among other factors [3]. The feeding process is also crucial to producing fish of adequate size for commercialization. However, regulating the amount of feed is not only relevant for fish growth but also to avoid water pollution caused by the excess feed that falls to the bottom of the ponds or cages [4]. Water quality needs to be considered as well, more so in inland aquaculture ponds, to provide a good environment for the fish to grow and live healthily. However, it is also important so as to avoid the pollution caused by increasing nutrient concentration in the water or by the persistence of antibiotics that increase drug resistance in fish [5]. Manually monitoring these factors is costly in labor as well as financially. For that reason, the introduction of sensor devices has extended worldwide. For example, different water quality indicators, such as salinity or turbidity, can be monitored using conductivity sensors based on electrodes or induction or optical sensors, respectively. The surge in the availability of monitoring systems for aquaculture has enabled the introduction of smart functionalities that allow automation and the incrementation of the controlling activities important to optimize the production of fish, increment their quality, and improve the sustainability of aquaculture facilities. Therefore, various mechanisms control the variables affecting fish in aquaculture facilities. These controlling tasks are performed with the use of actuators. Water quality for inland ponds can be controlled through pumps [6; 7], filters [6; 7], and aerators [6; 8]. Heaters are utilized to adequate the temperature to that needed by the fish [6]. Although electrical heating is the most common form of temperature regulation, there have been proposals for solar [9] and geothermal [10] heating as more sustainable and affordable solutions. Artificial lights have also been used to modify the behavior of fish, such as the swimming depth of salmon [11]. Furthermore, feeders provide automation functionalities to aquaculture systems [12]. It is also important to notice that not only the devices but the cages are also evolving, such as the addition of a nervous system based on the introduction of circuitry in the net for damage detection [13]. Nevertheless, this solution is extremely costly.