Aeration in a Pond

Why is aeration necessary in my pond?

Fish, snails, and tadpoles all need oxygen to survive underwater. The invisible life, like bacteria, that keep the water clean also require oxygen to keep the pond healthy. Oxygen enters the pond by diffusing into the water from the atmosphere. Submerged aquatic plants also produce oxygen during the day. Decomposing algae and fish waste, plus the normal respiration of aquatic life, use up the oxygen faster than it can diffuse back into the water. This is especially true during hot summer months. The warmer the water is, the less oxygen it can hold. You must run an aeration device like a fountain or waterfall 24-hours a day, especially in summer. Do not turn off the pump at night. The pond will continue to use up the oxygen. You could wake up to dead fish floating on the surface.

What is the best way to aerate my pond?

The best way to get oxygen into the water is through vigorous surface agitation. Agitating the water surface with a waterfall or fountain will drive oxygen into the water. A slow trickle however, will not sufficiently aerate the pond. An air pump and air diffuser will also agitate the surface and add oxygen to the water. Keeping the pond clean also

helps increase the oxygen-holding capacity of the water. Decomposing algae, plant leaves, uneaten fish food, and fish waste use up oxygen. By reducing the “oxygen demand” caused by decomposing organic matter, the oxygen level will naturally increase. Clean your pond filter at least once a month. Remove dead plant leaves before they begin to rot.

Do I need to aerate in winter?

If your winter season is mild (the fish still feed), you should keep the pump and filter running. Although the fish are eating less food, they still produce waste that consumes oxygen. If your pond normally freezes, turn off the pump and filter, but keep some type aeration on. Dormant fish still need oxygen under the ice. When a pond is frozen, naturally occurring gases (hydrogen sulfide and methane) cannot escape. Keep a small section of the pond open with a fountain or air pump and diffuser. This allows toxic gases to escape and adds oxygen to the water.