Generally, koi fish live up to 50 years but one of their kind, a scarlet koi fish named Hanako, was the longest living fish ever recorded. She died at the age of 226 years and it’s still a mystery why a fish would live for so long. The majority of people stick to the opinion that the fish simply enjoyed its life, receiving the love and care of her owners and the ability to swim in the clear waters of the Japanese mountains.