Aeration
The function of an aerator is to agitate the water and cause turbulence which exposess a greater surface area of water to the atmosphere while the air bubbles produced facilitate the absorption of oxygen.

If certain river fish are kept in a tank then an aerator would be a necessity as fish from fast flowing water demand more oxygen.

What then is an aerator?

It is simply an apparatus that will introduce a regular supply of air into the tank of water.

The two basic types of aerator are mechanical and non mechanical.

Mechanical aerators are usually driven by electric motors and are either small air piston pumps or diaphragm vibrators.

Both are available in various price ranges but the quieter and more efficient piston pump is usually more expensive.

The piston pump has a longer working life and it will produce sufficient air for several aquariums. For the fancier with only two or three tanks, however, the diaphragm type should be quite adequate.