During the colder months you will find that pond fish will slow down and their metabolism will slow also. When this happens they are unable to digest high protein or summer foods.
Feeding high protein summer food will is mainly to build up body fat and increase growth and colour.
If the temperature goes below 4°C, we would recommend not feeling the fish. they will not starve they will graze on algae and waste in the pond.
Always try and keep an area free from ice. This can be done either by keeping your pond pump running but raising it from the top of the pond to keep a slightly warmer ares at the bottom of the pond. You can use a pond heater that will float and keep around 18inch free from ice.
This is to allow any toxic Carbon Dioxide to disperse from the pond water.