In the cold weather spring and fall when the night-time temperature goes below 55° F (13° C) feed the Cold Weather formula.
When the pond water's temperature drops, the fish requires a highly digestible cool-water diet. The cold water diet is made with lesser amounts of protein but contains wheat germ which is easily digested and also contains a higher level of fats.
Before considering buying any additional fish for your pond you should consider whether your pond is ready for its first fish (if a new pond) or is ready for some extra fish if an existing pond.