Imagine living well over 100 years and enjoying relatively good health. Think of the things you could accomplish, the people you could meet, and everything that you could learn. Most of us will never live anywhere near that long. According to the National Ledger, the country with the longest life expectancy is Monaco, with an average of 89.73 years1. Some species of animals have the potential to live much longer lives, many of whom could be passed onto family members for one or even more generations.
One of the longest lived species commonly kept as pets are Koi fish. Koi are colored carp. Naturally carp are fairly drab in color which varies from silver, gray, olive, and black. The history of Koi is somewhat unclear, but at some point either the Chinese or Japanese (or both) began to breed carp selectively for colors such as red, orange, black, white, gold, cream, blue or yellow4. Regardless of where selective Koi breeding began, they have become very popular in Japan and the Japanese have refined the fish to its current status2.
Carp are a hardy species that can survive a wide range of water quality and water temperatures. It is this hardiness that has allowed them to be transported around the world where they are kept as ornamental pond fish. Most reports on the average life expectancy of Koi varies dramatically, ranging anywhere from 20-105 years, depending on the source5,6,7.
Some Koi however have been documented to live much longer. Such is the case of “Hanako” a red Koi that was hatched in Japan in 1751 and died on July 17, 19773. You may be asking how such a thing could be documented. The age of fish can be reliably documented by analyzing the rings on their scales much in the same way that the age of trees are determined, counting the number of growth rings in the wood3. These annual rings on a fish’s scale are too small to be read by the human eye and so must be analyzed with the use of a microscope3.
Hanako is a female Japanese name meaning “flower girl5. Hanako” spent her life in a pond in Gifu Japan with three other Koi who all lived to be over 100 years old8. What a remarkable experience to share the lives of such long lived pets. “Hanako’s” last owner was told by her grandmother (who died at the age of 93 in about 1960) at the time of her marriage into the family, “That carp has been handed down to us from olden times; you must take good care of it”.
Koi are very personable and will rise to the surface of the water when the owner comes out to their pond and you can even hand feed them. “Hanako’s” last owner claimed that she would come when she called to her3.
The wide range of reported life expectancy for Koi probably has to do with variation of individual genetics, but are probably due in a large part to differences in water quality and nutrition. This was obviously understood by “Hanako’s” human family who evidently provided her with the best possible environment. “Hanako” was loved in life by generations of her human family and I am sure was sorely missed when she died.
1. http://www.nationalledger.com/lifestyle-home-family/life-expectancy-by-country-201-185296.shtml
2. http://www.koifishschool.com/japanese-koi-carp.html
3. http://www.fishforums.net/index.php?/topic/34936-226-year-old-koi/
4. http://www.squidoo.com/koifishcolors
5. http://en.wikipedia.org/wiki/Hanako_(given_name)
6. http://www.koiacres.com/support-2/koi-fish/how-long-koi-live.html
7. http://wiki.answers.com/Q/How_long_do_koi_carp_live
8. http://answers.askkids.com/Nature/how_long_do_koi_live
9. http://www.pondkoi.com/forum/index.php?topic=70.0
