Koi ~ Cyprinus rubrofuscus

Koi are one of the most iconic and visually striking ornamental fish in the world, celebrated for their vivid colors, intricate patterns, and graceful swimming behavior. Originating from the common carp of East Asia, koi have been selectively bred in Japan for centuries to produce a wide range of color morphs including red, white, black, yellow, orange, and metallic varieties. Their calm nature, long lifespan, and majestic appearance make them highly prized for garden ponds, water gardens, and large indoor or outdoor aquatic displays.

• Size: 18-36 inches depending on variety and pond size

• Lifespan: 20-40+ years, with exceptional individuals surpassing 60

• Temperament: Peaceful, social

• Group/Solitary: Social; best kept in groups

• Food: Omnivorous, high-quality pellets, algae, aquatic plants, insects, crustaceans, seasonal nutrition adjustments for temperature

• Water Requirements: 59-75°F, pH 7.0-8.5, strong filtration, high oxygenation

Koi thrive in large ponds with ample swimming space, strong biological filtration, and reliable aeration. Their high metabolic rate and large adult size require powerful filtration systems and regular maintenance to keep water clean and stable. While they tolerate a wide range of temperatures, gradual seasonal shifts are ideal, and they should not be exposed to rapid changes or prolonged freezing conditions without proper depth and winter safeguards. Their diet benefits from seasonal adjustments, including wheat-germ formulas in cooler weather and higher-protein diets during warm months for growth and coloration. Koi are gentle giants and can be kept with goldfish and other robust pond species, though smaller fish may be eaten incidentally.

In the wild, their carp ancestors inhabited slow-moving rivers, floodplains, and sediment-rich ponds across East Asia. Modern koi, however, are entirely the product of selective breeding, with varieties such as Kohaku, Sanke, Showa, Ogon, and Asagi developed through careful lineage management. Their stunning colors and patterns are influenced by genetics, diet, sunlight exposure, and water clarity, making pristine pond conditions essential for showcasing their full potential.

Fun Fact: The oldest recorded koi, named Hanako, lived to be 226 years old, making koi one of the longest-lived vertebrate animals ever documented.