Overwintering Baby Koi in an Above-Ground Pond: Risks and Options

Above-Ground = Colder

30-inch deep above-ground pond in NY freezes deeper and faster than in-ground. Babies have higher oxygen demand and less fat reserves.

Survival Strategy

• De-icer + aerator (air stone at bottom) mandatory.
• If >6 babies lost in 2 weeks, oxygen is likely too low.
• Bring fry indoors (stock tank in garage at 40–50°F) for first winter.
• Many breeders do this routinely.

Resource

Overwintering guide: fishpondinfo.com/winter.htm