What Are Koi?

Sometimes, people immediately associate the word "koi" with goldfish, perhaps interpreting it as an Asian word for the beautiful gold fish that we now enjoy in aquariums and ponds.

Koi are a Far East species, having been developed in Japan around 200 years ago, but they are not a member of the goldfish family. However, they are distant cousins, since the goldfish and koi are both members of the carp family. But even though common varieties like the Comet goldfish can often grow fairly large, especially in outdoor ponds, they really don't look like, or compare to the size of koi, which can reach 24-36 inches!

They are also one of the longest living fish known to man. In the mid 60s, Dr. Komei Koshihars, then president of Nagoya's Womens College in Japan, had two scales from her beloved koi Hanako, examined by experts. Long living fish, can produce ridges or "rings" on their scales, which serve the same purpose as rings in a tree trunk, to verify age. Hanoko at that time, was deemed to be 215 years old, and five others in the pond ranged from 139-168 years old. But for the average fish fancier, you're looking at ages of 25-35 years.

Koi grow very well in outdoor ponds, often reaching 18 inches by 3-4 years of age, depending on the space they have, the quality of food, and the overall condition of the water. A pond that is well aerated and filtered, is far healthier than stagnant water.

The fact that they do grow so large, means bringing them indoors in winter, can be difficult. If your pond is deep enough so that the water does not freeze completely, they will over-winter without a problem.

Your Comprehensive Resource on Creating the Best Tropical Fish Tank Possible

The Encyclopedia of Exotic Tropical Fishes for Freshwater Aquariums is an inspiring resource. The book is separated into two sections, with the first part encompassing six chapters of both general and specific fishkeeping information and the second part offering detailed profiles of 1000 freshwater species. All fish enthusiasts will appreciate the down-to-earth writing style and superb images by some of the world’s top photographers. This practical reference also features anatomical drawings, multiple tip boxes, and over 2800 full-color photographs.

Click here to find out more and get your copy.

Save On Your Fish Supplies

Get special savings on premium fish food, filters, aquariums, medications and more at Petco. Click here for savings. Find everything from aquariums & bowls to filters to heaters.