4-feet Click to see full answer. Similarly, you may ask, what is the ideal depth for a koi pond? 2 feet One may also ask, how cold is too cold for koi fish? Temperature Range According to Koi Acres, a company that sells koi and koi supplies, koi fish are able to survive in water that is anywhere between 34 and 90 degrees Fahrenheit. Even though koi can survive in extremely cold or very hot water, it does not mean that they do well at these temperatures. Simply so, what do I do with my koi pond in the winter? These are the 4 winter Koi care methods we recommend for you to consider. Keep your koi in the pond for Winter. Move koi to a holding tank inside a garage or enclosed space. Build a greenhouse to cover your pond. Cover your pond with solar cover used for pools. How deep of water do fish need in the winter?Unless you live in an extremely frigid climate, your pond is at the minimum depth required for overwintering fish in a pond. Though 24 inches or deeper is better, 18 inches should give your finned friends enough room to ride out the cold temperatures—as long as you keep a hole open in the ice.
