Designing a photovoltaic system that aims to pumping air in fish tanks by air pump in order to meet the fish needs of the vital oxygen. The system consists of two circuits, load circuit and control circuit. 1. Circuit load: solar panel, Battery, charge controller and Inverter. 2. Circuit control: relay 12 V, pic microcontroller 16f877A, Transistor BC547, Diode 1N4148, Crystal 4MHZ and Capacitor 22 Pf. The analysis shows the configuration of photovoltaic 400W, 1battery of 200 Ah,  inverter 1 kW and 4 charge controller 10 A. This is the most economically feasible and average cost of energy (ACOE) is about 2.6 EG₱/kWh. . “Dissolved oxygen" or DO, and is measured in parts per million or ppm in fish tank rise above 3 (stressed level).