Generally, pond fish do not need feeding in the winter, unless there is a long mild period where water temperature rise consistently above 10 oC. Ensure there is sufficient oxygen in the pond by ensuring the pond is never fully frozen over by using an energy efficient heater like an Affinity Ice Vent this is much more successful and convenient than the old trick of using a tennis ball or hot water to retain an ice free area, which are in reality only short term solutions.
NEVER break the ice on your pond with something like a hammer as the shock waves may kill the fish.
Continue to remove dead plant matter from the water to prevent pollution.
When the surface of the pond is frozen, leave the pump running for circulation but turn off fountains and waterfalls to prevent the pond emptying.