Special food for Koi and other valuable pond fish at temperatures below 12°C (54°F). sera KOI Professional Winter Food is a staple food for Koi and other valuable pond fish at low temperatures according to their natural requirements. The essential, highly unsaturated omega-3 fatty acids [Eicosapentaenic acid (EPA) and Docosahexaenoic acid (DHA)] provide energy and protect the cell membranes. The food is particularly easy to digest due to the reduced carbohydrate amount. The food quickly sinks down to the bottom where the fish dwell and look for food during winter. It is excellently suited for feeding at temperatures below 12°C (54°F).