Koi Pond Basics: Depth, Filtration, Winter Care & Feeding

For a healthy koi pond in Vermont (-20°F winters):

Pond Specs

• Minimum 1.5 m (5 ft) deep.
• At least 10,000 L (2,600 gal) for 2–3 koi.
• 1 koi per 5,000 L with natural filtration.

Filtration & Circulation

Essential. Choose natural (plants/substrate) or mechanical/biological filters. A solar fountain alone won't suffice—you need 24/7 circulation and oxygenation.

Winter Survival

Koi tolerate ~7°C (45°F). Pond must not freeze solid. Keep a hole in ice for gas exchange. Covering helps.

Feeding

Supplement natural forage (mosquito larvae, algae) with quality koi food. Homemade: brown bread, corn, peppers, oranges, lettuce.

Water Changes

Replace 10% weekly to control ammonia, nitrite, nitrate, and replenish minerals.

Source Fish

Pet store koi can be hardy if pond meets specs. Breeder koi may need more care.