The average life expectancy for koi fish outside of Japan is about 15 years, while its 40 years in Japan. Reportedly, koi fish can live for much longer in the optimal conditions and there are supposedly many koi who live over 100 years.
For the most part these are just rumors and most koi only live for a few decades. However, the oldest koi on this list lived for over 200 years and had its age scientifically verified.
The other koi on this list might not have lived as long, but their ages were publicly noted and they were in the news for being some of the biggest koi ever.
4. Big Poppa (Unknown – Present)
Oldest Age Reached: over 7 years old in 2017
Location: Katy, Texas, USA
Owner(s): Nelson’s Water Garden
Big Poppa is a mysterious large koi that has been living the pond of Discovery Green Park in Houston for over six or seven years. The park says that they don’t know how or when exactly Big Poppa came to the park. However, park visitors had noticed the large koi fish for several years and in 2017 the park got to see just how massive Big Poppa really is.
Discovery Park had to drain the lake to fix a leak, which meant they had to catch Big Poppa and place him in a temporary container. According to Ren Mitchell, marketing manager for Discovery Green, everyone was shocked by how large Big Poppa was when they finally caught him. Mitchell estimates that Big Poppa is more than 2 feet (0.6 m) long and over 20 lbs (9.07 kg). After being removed from the park’s lake, Big Poppa was relocated to Nelson’s Water Garden in nearby Katy, Texas.
3. Big Girl (c.1990 – Unknown)
Oldest Age Reached: 17 in 2007 (last news from this time)
Location: Melksham, Wiltshire, England
Owner(s): Geoff Lawton
photo source: The Daily Mail
In late 2007, a koi named Big Girl was in the news for being the world’s biggest koi fish. Big Girl weighed in at a whopping 90 lbs (40.8 kg) and was 4 feet (1.2 m) long!
Big Girl’s owner Geoff Lawton bought the monster koi from a specialist breeder in Japan. Lawton, who owns Rainbow Koi shop in Wiltshire, England said that Big Girl was the largest koi ever exported out of Japan and that there had never been a koi as large as Big Girl in Britain before. At the time, Lawton was keeping Big Girl in a special show pool at his fish shop and said that he had no plans to sell her. Lawton added that if he ever decided to sell Big Girl he wouldn’t take anything less than £30,000 (about $40,000).
2. Portland Japanese Garden Koi (before 1996 – Present)
Oldest Age Reached: around 22 years old in 2018
Location: Portland, Oregon
Owner(s): Portland Japanese Garden
photo source: Flickr via Paul VanDerWerf (Picture is of koi pond at Portland Japanese Garden. The oldest koi is not pictured here.)
The Portland Japanese Garden is home to about 50 koi and is one of the most popular features of garden. The koi pond has been a fixture at the Portland Japanese Garden since the 1970s.
According to Senior Gardener Adam Hart most of the garden’s koi fish have records and names. Hart said that the life expectancy for most of the koi at their garden was about 30 years. He added that many visitors want to know which one of the koi is the oldest. While the garden isn’t absolutely certain, after looking through historic photos, they found one male koi who has been at the garden since at least 1996. This koi would be about 22 years old today.
1. Hanako (c. 1751 – July 7, 1977)
Oldest Age Reached: 226 years old in 1977
Location: Higashi-Shirakawa Village, Japan
Owner(s): Dr. Komei Koshihara
photo source: Wikimedia Commons
Hanako is probably the most famous koi fish ever in history due to her astonishing age. When Hanako died in 1977 she was believed to be 226 years old, making Hanako the oldest koi fish ever in the world.
Hanako’s amazing story was first brought to light when her last owner, Dr. Komei Koshihara, made a national broadcast on Nippon Hoso Kyokai radio station to all of Japan. Dr. Koshihara explained how he had inherited Hanako from the maternal side of his family. At the time of the broadcast, Hanako was 215 years old, weighed 7.5 kg (16.5 lbs), and was 70 cm (27.6 in) long.
Dr. Koshihara knew Hanako’s age because he had it verified by professor Msayoshi Hiro who worked
at the Laboratory of Animal Science of the Nagoya Women’s College. Two of Hanako’s scales were extracted and analyzed for two months. Professor Hiro was able to count the rings of growth on Hanako’s scales to determine her age.