Available online at: https://proceeding.researchsynergypress.com/index.php/cset RSF Conference Series: Engineering and Technology ISSN 2809-6843 (Online) | 2809-6878 (Print) Volume 1 Number 2 (2021): 1-13 Corresponding author Junaedi, 1911600151@student.budiluhur.ac.id DOI: 10.31098/cset.v1i2.460 Research Synergy Foundation Smart Fish Farm Based on IoT Aas Monitoring to Reduce The Number of Death in Guppy Fish Junaedi 1 , Wendi Usino 2 1,2 Information Technology Faculty, Budi Luhur University, Indonesia Abstract During the transition from dry season to rainy season or vice versa, very high temperature fluctuations often occur, causing large number of deaths in guppy fish farming. The death of this guppy fish is also triggered by water conditions that are not maintained. Therefore, a system that can monitor water conditions in real time without being limited by distance, and that can cope the drastic temperature changes is needed. If water conditions can be monitored in real time, of course, the guppy fish in aquarium or tank will become healthier, well-maintained and will produce the best quality guppy fish. For this reason, the researcher makes a system that is able to monitor the condition of water in the aquarium to reduce the number of deaths in guppies. The researcher conducts trials using Fuzzy Mamdani method of three input variables from water temperature sensor, pH sensor and turbidity sensor which defuzzification result shows crips output value at 44.63. That result puts water condition in “Fair” level, and when it is matched with the calculation result of matlab r2013a using Fuzzy Mamdani, the result is 44.8 which is not far different. The result of this study is a smart fish farm system that can monitor water conditions in aquariums or tanks, such as: feeding time, checking and controlling temperature, monitoring water pH, monitoring water turbidity levels, lights control that can automatically turn on and off with room lighting indicators, and drain when the water is turbid. This smart fish farm system is made with an Arduino microcontroller that is connected to the internet based on Internet of Things (IoT) and the Mamdani Fuzzy Logic method. This smart fish farm system can also store records with platforms from Thingspeak and MitApp for the mobile applications making. Keywords: Internet of Things (IoT), Guppies, Smart Fish Farm, Fuzzy Logic, Microcontroller, Arduino, Thingspeak, MitApp This is an open access article under the CC–BY-NC license INTRODUCTION Interest in fish, especially guppies, during a pandemic like now is increasing. Therefore, a strategy or specific effort is needed to be able to meet market demand. One of the obvious efforts to fulfill this demand is adding the number of tanks (aquarium) for farming progress, which is done by a privately owned guppy fish farm located in Tangerang Regency. These tanks are the place where the guppies are put during farming progress until they are ready for sale. This progress stage is the most important thing to obtain the expected result. Due to the large number of tanks, not all fishes are well controlled during the farming progress. Many fishes die before they can be sold, resulting in crop failure. This crop failure factor affects the decrease in the amount of fish production and turnover. To overcome this crop failure, it is necessary to monitor water temperature, water pH and water quality in the aquarium at all times to achieve the expected results. With well-maintained water quality, good temperature, and suitable water pH, guppies with attractive appearances can be produced, such as: wide tail shape, proportional body shape and not susceptible to disease. To maintain good water quality, water