- Koi fish are a type of domesticated carp that were selectively bred for their bright colors and patterns. They originated in Japan, where they were originally kept as food fish, but eventually became popular as ornamental fish.
- Koi fish are known for their long lifespans. In ideal conditions, they can live for up to 30 years or more! The oldest koi fish on record lived to be 226 years old, but this is extremely rare.
- Koi fish are omnivores and will eat just about anything, including insects, plants, and small animals.