Koi can survive winter in a pond as long as certain conditions are met. The pond must be deep enough—typically at least 3 to 4 feet in colder climates—so the water below the ice remains at a stable temperature where the fish can remain dormant. During winter, koi enter a state of torpor, where their metabolism slows down and they become inactive, resting near the bottom of the pond.
It’s crucial to maintain an opening in the ice to allow for gas exchange, which can be done with a pond heater or aerator. Without this, harmful gases can build up under the ice and threaten the koi’s health. Feeding should stop when the water temperature drops below 50 degrees Fahrenheit, as koi can no longer properly digest food.
