This process takes place at the water surface, the interface between water and air.

The most efficient way to increase oxygen levels in water is to move and agitate the surface (without causing stress to aquarium inhabitants).

The greater the surface movement, the greater the oxygenation rate. Symptoms of oxygen deficiency sometimes occur in heavily stocked aquariums and are demonstrated by fish exhibiting exaggerated and rapid gill movement. It is important to note that temperature is also a factor. Higher temperatures result in lower dissolved oxygen levels.

Planted aquariums should employ gentle surface movement. This will reduce carbon dioxide loss, a key element of photosynthesis for plants.



Power filters and powerheads are much more efficient in oxygenation versus air pumps, because of greater water movement over a much larger water surface area.