We don’t want to frighten anyone, but the following sad story happened last year and did NOT repeat itself this year: A pond owner unexpectedly needed to go abroad at short notice and delegated the feeding of his still active koi and carps (in moderate external temperatures of around 10 °C, in a very large natural pond) to his father-in-law. The father-in-law merrily fed the pond fish with the sort of food you can buy in any DIY store. The food had no temperature recommendations for the feeding. The last feed took place in the afternoon before the disaster occurred. During the night there was a temperature drop from about 15 °C to – 5 °C. An ice cover formed overnight and, because the temperature didn’t rise again, it became thicker and thicker. During the course of the following day more and more dead carp and koi could be seen floating directly under the ice cover. In the course of time the dead animals froze in the ice. The photo shows the pond at that time. When the owner returned all his animals had perished in the pond and he rang me. From his description of the events we identified the food/feeding as the cause of death. The pond was then newly stocked with 70 koi and for low temperatures between 5 and 15 °C JBL ProPond Winter M was purchased. As the temperature dropped again a few days ago no losses occurred and the animals are still visible swimming beneath the ice. It is essential that fish in low water temperatures are given easily digestible food with a protein/fat ratio of 2:1. This way you and your fish are on the safe side!