Once the water in your pond drops below 50 degrees, you can stop feeding your fish altogether until things warm back up to that same benchmark. Don't remove your pond filter until you stop feeding your fish, as it will be necessary to help remove the excess waste and nutrients from the water. Fish enter a period of dormancy in the coldest months where their metabolism slows dramatically and they rely on their stored fat to survive.
You can trigger your fishes' instincts to begin preparing for this period of dormancy by slowly reducing the frequency of feedings over time, starting with once the water's temperature drops below 70 degrees.
