Tilapia is one of the fish that has high economic value, easy cultivation method, and relatively affordable price. Tilapia can be kept in the lowlands of brackish water to the highlands of fresh water. However, tilapia is a fish that is very susceptible to disease, and loses its appetite when the water quality in the rearing pond is not maintained.
Therefore, we need a tool that is able to monitor water quality in tilapia aquaculture ponds in real time. The use of internet of things technology in the monitoring system makes it easier for monitoring activities to be carried out anytime and anywhere. The monitoring system is built with three main parts, namely Arduino mega 2560 WiFi IoT (Microcontroller), Firebase (Database), and Android Studio (Application). In this study the testing method consists of three stages, the first stage is application testing, testing the speed of data transmission and testing the accuracy of the data. After testing, it was found that the application has been running well, the average speed of data transmission from the microcontroller to the database is 7.85 Mbps with the required time of 5.4 seconds, while the speed of data transmission from the database to the database. application is 9.21 Mbps. with the required time of 1 second, and the data contained in the microcontroller, database and application has a 100% accuracy rate.