The amount and frequency with which you feed your pond fish during the winter depends largely on just how cold it gets in your area. When the temperature drops, do your fish make their way to the bottom of the pond and remain there, motionless, for long periods of time? This is generally a sign that they are hibernating and conserving energy, which means they need less food than usual. If they are swimming around actively, they'll generally still require sustenance. Let the temperatures and the activity level of your pond fish determine how much you feed them during the winter months.
Feed your fish at least a little bit during the winter months, provided they are swimming around actively. Many pond and fish experts agree that no matter how active they are, you shouldn't feed your fish the same amounts you do when the weather --- and water temperatures --- are warmer.
Reduce the amount of food you give your pond fish if they are mostly inactive, and stop feeding them altogether if they are hibernating --- laying motionless on the bottom of the pond. During these periods of inactivity, their digestive systems will not be able to handle much, if any, food, but the fish will eat regardless if you make food available.
Opt for food that contains protein and is highly digestible if you are going to continue feeding during the winter. This is important all year long, of course, but particularly so during stretches of cold weather, when your pond fish are less active than usual.
Some pond experts advocate that you stop feeding your fish altogether during the cold winter months. Others insist that doing so can affect the health of your fish when temperatures begin returning to normal. In general, it's a good idea to adjust your feeding practices based on the activity levels of your fish, but always keep in mind that no matter how active they are, their digestive process will be slowed by colder water temperatures, so avoid overfeeding.