Ornamental Fish Production and Management

4.1.2 Aerator

Aerator is an air-pumping device which is electrically operated. The device consists of a vibratory air pump – a tiny rubber diaphragm. When alternating current (A.C) passes a shaft bearing a magnet vibrates briskly under a magnetic field effect. As the shaft is attached to the diaphragm, the latter is allowed to vibrate up and down like a piston, producing a forceful stream of air. The air flow is then directed into the bed of the aquarium tank using plastic air tubing (thin pipe). At the opening, a diffuser (air stone) may be used to produce tiny bubbles of air. The aerator is a very useful handy device for small home aquarium. They are cheap, long lasting and need little maintenance. However, there are a number of drawbacks too. First, they produce an unpleasant, rather loud, humming sound. Second, they are ineffective in large and deep tank. It must be noted that an aerator does not generate fresh air. On the contrary, it only pumps out into the tubing the air of the surrounding. An aerator is likely to drive any fumes, chemical vapours and so forth alongwith the air into the aquarium tank which may prove harmful to fish. It should therefore not be operated if any such situation exists in the room.

Apart from its role in aeration of tank water, aerator has a role of air-lifting of water for filtration. In undergravel filter, an aerator is used to confine the rising stream of air-bubbles into a narrow vertical tube (the uplift pipe) to bring about air-lifting of water and any suspended particles in it.