At 226 years old, koi Hanako was the longest living fish ever recorded.
The oldest Koi ever recorded is a 226 year old Koi called Hanako.
Hoax or Fact:
The world's oldest fish is a Koi Carp called Hanako that went on to live for 226 years, that is what the stories in question say! Let us study if the unbelievable claim can be fact or not.
The Koi Carp fish Hanako (name translates to “flower girl” in Japanese) was a beautiful red colored female fish in Japan, which at 226 years old is often said to be the longest living fish ever recorded.
Hanako Koi Age Estimation
Komei Koshihara was the last owner of Hanako Koi, who inherited it from his past generations. Out of curiosity, in 1966, Koshihara wanted to estimate Hanako's age and took it to Professor Masayoshi Hiro, who analyzed the rings on its scales in Laboratory of Animal Science, Nagoya Women’s College for a period of two months. At that time, Hanako Koi was estimated to be 215 years old, weighing 7.5 kilograms and 70 centimeters long, which suggests it was born back in 1751. Most fish have growth rings on their scales known as annuli, and their age can be estimated in much the same way as one estimates the age of a tree by counting its rings. In Image Gallery you can see a picture of the Hanako Koi fish, another one showing one of her scales.
Surprised at their finding, Komei Koshihara and Masayoshi Hiro went on to examine the remaining five Koi Carp fishes in the same pond, and after a yearlong analysis, all of them were said to be over 100 years old. You can read the English transcript of Komei Koshihara's radio broadcast to the whole Japanese nation over the NHK radio station on 25 May 1966 on Pond, Koi and Plant Forum.
Koi Fish Lifespan
Hanako, which was thought to be the world's oldest koi carp, died on a memorable date 7/7/77 (7 July 1977) at the age of 226 years. However, many Koi breeders are reluctant to believe it and the age examination has been questioned.
Koi fish are a group of ornamental varieties of domesticated common carp that are kept in outdoor koi ponds or water gardens. How long they live depends on how well they are cared, but the generally accepted lifespan is 25-35 years; the greatest authoritatively accepted age being little more than 50 years. Hanako seems to be cared well by several generations of Koshihara's family, and the Koi used to respond and come to him when he called. However, there are no credible records of Koi which lived over 100 years. An author Nick Fletcher wrote in his book 'The Ultimate Koi’ (Editor) that the testing for estimating Hanako's age was not detailed, and could be an overestimation of age drawn out of wrong conclusions from scale readings. Notably, Komei Koshihara was the President of the same Nagoya Women's College, where the testing was held, and it was a time when Koi fishes were popular for business as well. The 226 year old Hanako Koi was repeatedly talked among koi enthusiasts, and it even made into an article in the UK’s Guardian (theguardian.com).
So lack of other credible examinations to estimate the actual age of Hanako Koi do not validate the attributed 226 years age. Either Hanako actually lived in a fountain of youth, or the examiners botched the science.