Oxygen is an important element of any healthy pond supporting fish, or any other live animals. These animals draw oxygen from the water column to respirate underwater. Adding supplemental oxygen through a pond aeration kit helps keep your fish alive during the summer when oxygen levels are naturally at their lowest point. It helps with the Denitrification cycle to off-gas nitrate. It can help keep a hole in the ice during the wintertime. Pumping in oxygen through these kits is a smart decision for all koi keepers.