Surface area is all important to the oxygenation of the pond water. Aeration increases the surface area of water that comes into contact with the air.
In warm temperatures, the amount of oxygen that can be dissolved in water decreases. At the same time, fish are more active in warmer temperatures and thus their requirement of oxygen is greater.
The complete opposite happens in cooler temperatures where the water can dissolve plenty of oxygen.
Fish that are deprived of oxygen may cause suffocation. Symptoms include:
- Gasping at the water surface.
- Congregating near oxygen sources.
- Fish may stop eating.
- Too much of Carbon Dioxide (CO2) in the water can also lead to Oxygen Starvation. As a bi-product of photosynthesis and respiration, plants produce Carbon Dioxide at night. High levels of Carbon Dioxide can decrease pH levels, thus oxygenation is essential.
One way to increase oxygenation is through aeration from either a returned filter outlet, a waterfall, a fountain or an air pump. Water returned from a filter can agitate the waters surface thus increasing the surface area and in turn, the amount of oxygen the water can dissolve. Air pumps will also create oxygen rich water by introducing oxygen directly into the water along with the fact that submerged bubbles will increase the waters surface area. Many smaller bubbles provide a greater water surface area when they submerge compared to fewer, larger bubbles.