Koi Hanako was the longest living fish ever recorded

Hanako’s actual age was verified by analyzing the rings on her scales. Much like how dendrologists determine the age of trees by counting the number of rings of growth on wood, the rings of growth on the scale of Hanako was counted using a light microscope. The growth rings on the scale shows a pattern of wide growth followed by a narrower growth. The differences in the width of the rings reflect the seasonal change of summer and winter.

During the summer, fish eat more and grow more resulting in a wider growth ring pattern. The narrower growth represents the slower metabolism during the cold icy weather. In order to analyze the exact age of Hanako, she was extracted from the pond in the deep mountains of Mino Province.

Two scales from different parts of her body were taken off with tweezers. The individual annual ring on the scale was painstakingly analyzed over a period of two months in Laboratory of Animal Science, Nagoya Women’s College by professor Masayoshi Hiro. Both Dr. Koshihara and Professor Hiro were delightfully surprised when Hanako was discovered to be 215 years old at the time.

Following this discovery, the remaining five koi carp in the same pond was examined as well. After a yearlong analysis, the results showed that they were all over 100 years old as well.

While nobody knows the exact reason for her amazingly long lifespan, perhaps the crystal clear waters of the Japanese mountains in addition to the great love and care of her owners was the key. Koi carp is generally a long-lived fish with a lifespan of approximately 50 years.

However, there are many carp that lives over a century. This is one of the reasons why the koi carp have gained so much admiration in Japan and the rest of the world as well. Koi Hanako, is a great example of the how long living koi carps truly are. Next to whales, turtoises, and tuataras, koi are one of the longest living vertebrae on Earth.

http://fishlaboratory.com/fish/koi-hanako-longest-living-fish-ever