Not only does your fish require oxygen from the aeration of the pond water to survive, but your beneficial bacteria also require it. Your pond will become anaerobic without oxygen, which is why aeration is crucial. When it comes to decomposing organic material, anaerobic bacteria are less effective than aerobic ones. Furthermore, as anaerobic bacteria break down organic material, they release hydrogen sulfide and carbon dioxide, which gives the pond a rotten egg odor. Beneficial bacteria, on the other hand, break down sludge and debris and release a harmless gas. The addition of aeration to your pond maintains its aerobic system by raising the dissolved oxygen content of the water.
Although fish do occasionally perish, low oxygen levels are frequently the cause of large numbers of fish deaths at once. When the pond freezes over in the winter, the gases created by the decomposing organic garbage might get trapped and restrict the amount of oxygen accessible for your fish. If enough oxygen is displaced, your fish can suffocate. Because it will provide new oxygen into the pond and maintain an opening in the ice that permits gas exchange, aeration is crucial. Fish kills can occur in the spring and fall as a result of stratified water turnover episodes. A stratified pond quickly mixes during a turnover event, reducing the oxygen content of the top water as it mixes with the oxygen-starved bottom water. Aerating pond water will remove the thermocline and stop turnover in the spring and fall.