Aerating an aquarium is very important to the overall health of the fish in the aquarium. Aerating an aquarium accomplishes two goals. First, it increases the amount of oxygen in the aquarium. Second, it reduces the amount of toxic gas that is built up from biological waste.
Methods of Aerating an Aquarium
There are several methods to aerating an aquarium. The most common way is to use an air stone or an air wand. Air is pumped into the air stone or bubble wand and diffused, leaving tiny bubbles that float to the top of the water. These air bubbles help to exchange good, clean air with the water.
Another way to aerate an aquarium is with the use of wet/dry environments. This is often accomplished with a wet/dry filter in a sump. The water is dripped through the air and then runs through a stack of bio filter material such as bio balls. This method is quite effective because the water is exposed to air on all sides. This method also allows for the growth of bacteria on the wet/dry media.
Biowheels can also be an effective method of aerating an aquarium. Biowheels work much like wet/dry setups, but usually on a smaller scale. Instead of dripping water down through some media, the water is picked up by the biowheel and spun though the air.
There is never a situation where too much air exchange is a bad thing for aerating an aquarium. I often use multiple methods for aerating an aquarium. My favorite method is the wet/dry filter because you get the advantage of increased bio filtration along with increased aeration.