Where Gas Exchange Occurs
Oxygen enters aquarium water almost entirely at the surface of the water, and to a much lesser degree when bubbles pass through the water column. At the same time, carbon dioxide is given off. The larger the water surface, the greater the gas exchange opportunities. Therefore, a short wide tank is better than a tall skinny tank that holds the same amount of water. Keep that in mind when purchasing and stocking your aquarium.
When More Aquarium Aeration Is Needed
Even a healthy aquarium will sometimes require additional aeration. As the temperature of the water increases, it will hold less oxygen. The same is true when salt is added to aquarium water. The more salty (saline) the water is, the less oxygen it will hold.
Certain medications can impact the oxygen a fish can take in, so it is often wise to provide additional aeration when medicating your fish. Last, but not least, anytime stocking levels in the tank increase, more oxygen will be used. So keep aquarium aeration in mind when you add fish to your tank.
- When water temperature is elevated
- When water is more brackish
- When treating fish with medications
- When the tank is heavily stocked
In most tanks the water return from the filter is sufficiently aerates the water. However there are times when additional aquarium aeration is necessary. Moving the water increases the rate of gas exchange considerably. There are several ways to increase the gas exchange in your aquarium.