For the purpose of this diploma paper we have built an independent system which enables automated fertilising, aquarium cooling process and on/off switching of the lights. Automatic functions make the aquarist's work easier and are a great time saver. The system is based on the development microcontroller board Arduino Mega 2560 and its components. For developing the system the programming language C/C++ adjusted to Arduino was used, along with the Arduino development environment and Visual Studio 2013. The system comprises four pumps providing automated fertilising, a relay providing on/off switching of the lights and a temperature sensor providing on switching of the computer ventilator for water cooling. All together is controlled and operated/adjusted on the display and 4x4 keyboard.