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Koi

Cyprinus rubrofuscus

FishIntermediate care

🌍 Overview

Koi are ornamental varieties of the Amur carp, developed in Japan starting in the early 19th century from food carp that displayed unusual color mutations. Breeders selectively refined these mutations into today's dozens of recognized color patterns — kohaku, showa, and sanke among the most prized — which are still judged competitively at shows in Japan. Koi are exceptionally long-lived and develop genuine recognition of individual keepers, often gathering at a pond's edge when a familiar person approaches.

📋 Quick Facts

Native Range

Japan (developed from Amur carp of East Asia)

Natural Habitat

Outdoor ponds and slow-moving freshwater systems; entirely domesticated as a pet

Adult Size

12–36 inches (30–90 cm) depending on pond size and variety

Wild Diet

Omnivorous bottom feeder — aquatic plants, insects, and crustaceans

Wild Lifespan

25–35 years typical; some documented individuals far longer

Conservation Status

Domesticated (not evaluated; wild ancestor Least Concern)

🤓 Did You Know?

Koi are famously long-lived, with some individuals in Japan documented living well past 70 years and one famous fish, Hanako, claimed to have reached 226 years old (a figure that remains disputed among scientists but reflects just how extraordinarily long-lived the species genuinely can be). Koi also recognize individual people and will learn to approach a familiar keeper at the pond's edge for food.