Pond Fish Basics: Goldfish, Koi, Orfe, and Winter Survival

Simple questions: Only goldfish/koi in ponds? Winter survival with heater? General answers.

Best Pond Fish

• Comet/Common Goldfish: Hardy, colorful, breed easily. Survive Canada winters in 24"+ depth.
• Koi: Need 1000+ gal, 3–4 ft depth, aeration. Live 40+ years.
• Golden Orfe: Surface schoolers, need 1200+ gal, high O2. Stunning but jump.
• Tropicals (Guppies, etc.): Die below 60°F. Not for outdoor ponds in temperate zones.

Winter "Heaters" = De-Icers

They don't heat the pond. They keep a 12" hole open in ice for gas exchange. Essential for koi/orfe. Goldfish often survive without if pond deep enough.

Winter Checklist

1. Depth ≥ 24" (36" for koi).
2. Air pump (diffuser at mid-depth) + de-icer.
3. Stop feeding <50°F.
4. Remove leaves/sludge in fall.
5. Net for herons.

Build it right, stock it right, and winter is a non-event.