Fish should be fed all year round in order to keep them active and healthy. Some fish will survive the winter months without food, although they then become lethargic and as their digestive system shuts down they don't ingest the vital nutrients they need to retain a healthy and effective immune system, hence becoming susceptible to bacterial and parasitic infections (they won't show symptoms of this till the beginning of the summer when bacterium multiplies more rapidly due to change in climate). Food needs to be changed during winter months to wheatgerm, this is more digestible.
Other types of pond specimens i.e. Sterlets need to be fed a high protein growth food all year round.
There is no set formula indicating how much food you should feed depending on the amount of fish you keep, however if all the food is not eaten within 2 minute net it out immediately as this is too much. For guidance please feel free to give us a call or Click Here to contact us for professional advice on this matter.