🐠 Fish & Amphibians

Koi

Living jewels for backyard ponds.

Koi are ornamental carp that can grow over two feet long and live for decades. They need large, well-filtered ponds.

Lifespan25–35+ years
SizeLarge · 15–36 in
Care levelModerate
Typical cost$30–80 / month
Great for
Pond ownersLong-term commitmentPeacefulSocialHardy
Koi

Photo: Asturio Cantabrio · CC BY-SA 4.0 · Wikimedia Commons

Care guide

Daily care

Pond of 1,000+ gallons, at least 3 ft deep, with strong filtration and aeration.

Koi pellets; reduce feeding in cold water.

Ample swimming space.

Regular water testing and maintenance.

Health

Common health concerns

Know what to watch for. Early detection makes most of these far easier and cheaper to treat.

  • Parasites
  • Ulcers
  • Koi herpesvirus
  • Fin rot
  • Oxygen deprivation
Veterinary care

Vet visits

Koi-experienced aquatic vet.

Find a vet near me

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This guide is general information, not veterinary advice. Costs are rough U.S. estimates for food, supplies and routine care. Always consult a licensed veterinarian about your pet’s needs.