Overwintering Koi in Upstate NY: Indoor Aquarium Success

Why the Pond Failed

Small preformed pond + upstate NY winter = freezes solid. Koi need 3+ ft depth or heated garage. Bringing them in with pond water + conditioner wasn't enough — no filtration, no aeration, no cycling.

Correct Indoor Setup

1. Tank: 100+ gal (stock tank OK).
2. Filter: Cycled canister or large sponge filter (seed with pond media).
3. Heater: 300W+ to hold 50–60°F.
4. Aeration: Air pump + stone (critical).
5. Light: 10 hrs/day (shop light) for plants/cycle.
6. Substrate: Bare bottom or gravel — your choice.
7. Plants: Anacharis, hornwort — absorb nitrates, add O₂.

Routine

• Feed sparingly (wheat-germ pellets) at 55°F+.
• 25% water changes weekly (dechlorinated, temp-matched).
• Test ammonia/nitrite 2×/week.
• Salt 0.1% for stress.

The 4 Fry

Separate tank (20 gal) — they need higher protein, cleaner water. Same params.