While netting is usually used in the fall to prevent debris from falling into your pond, netting can also be utilized in the winter to protect your fish from predators. Organic material can be particularly harmful to your pond in the wintertime. As leaves and other natural debris decays in the water, it releases toxic chemicals in the way of sulfur dioxide, ammonia, and CO2. Typically, these gases are able to leave the water through the surface of the pond and permeate through the air. However, if your pond is frozen over, gas is no longer able to escape.
One of the ways to mitigate any harm cause by this is to provide a hole in the ice in which the gases can escape. Additionally, reducing the amount of debris there is in the first place will prevent excess gas formation, and improve your water quality greatly.
