About Koi Fish

Koi fish, or Nishikigoi, are the product of several centuries of selective breeding of the common brown Asian carp and the German carp. The first color mutations appeared about 1805.

Koi are available in all colors from the purest white, through yellow, orange, red, near-lavender, blues, greens and coal black, in limitless combinations.

Most popular in Japan are the Kohaku, a pure white fish with persimmon-red patches arranged in a stepping stone pattern.

In the USA, favorite types run the gamut from the legendary "Big Three" (Kohaku, Taisho Sanke, and Showa Sanke, the last two appreciated for varying proportions of white, black and red) to the eye catching Ogons, metallic fish that look like they have been hammered from gold or platinum.

New developments are the long fin or butterfly Koi and the Gin Rin Koi, where each scale sparkles like a diamond.

Koi can be purchased from several importers of Japanese Koi, from pet stores or from garden centers. They are raised commercially in Japan, Singapore, Israel, and in most temperate American states, especially California. They are usually offered in sizes ranging from three to twenty-four inches. Japanese shows are filled with "Jumbos" which exceed three feet in length.

Koi starter fish may be purchased for as little as several dollars with nice fish going from about $25 to many hundreds of thousands of dollars.

Koi are omnivorous and will eat a great variety of foods. Special Koi food can be purchased. Many keepers supplement them with trout chow, catfish chow, bread, Cheerios, peas, lettuce, spinach, fresh shrimp, earthworms and krill. A real treat for Koi is watermelon. On occasion Koi have eaten slugs!

When Koi become accustomed to your presence, they will eat from your hand. Some have even been trained to take food from their owner's lips.

Koi dispositions are mellow and their toothless mouths are soft. They pose no danger to smaller fish. A twenty-four inch Koi can be safely housed with four inch Koi, common goldfish, or comets. Very slow moving fancy goldfish may have a problem competing for food.

Koi ponds can be constructed from concrete, Gahnite, PVC or butyl rubber liners, fiberglass tanks, or they can be housed in natural ponds (not a hole in the ground.) Ponds should be at least three feet deep with a minimum of three hundred gallons for each mature fish. Though Koi will survive poor conditions, they do best with good filtration and aeration. Remember, Koi do grow and under ideal conditions, they can reach two feet in three years.

It is not unheard of for a happy Koi to live thirty years. The record in Japan is two hundred and twenty-three years.

What jobs need to be done in springtime?

Test your pond water. This will give you an indication of the state of your pond after its seasonal break. Test specifically for pH and nitrate.

Change the UV bulb. Unlike a biofilter where the media will remain and be effective for many years, the UV bulb must be replaced each year to keep green water controlled. Spring time is the most logical time to replace the bulb as it's hardest work will be in the first 4 or 5 months of the season. Even if your current bulb appears to illuminate, its output will have deteriorated from last season, making it less effective against green water. Fit a new bulb now and you can forget about it for another 12 months.

Filter. If your filter has been turned off or even turned down over winter, it will have accumulated a good degree of solid matter. Springtime (sub-10oC) is a superb opportunity to carry out major maintenance as you are able to get away without upsetting its function (unlike summer filter maintenance).

If you have a friend who has been running a heated pond and filter over winter, ask if you can borrow some of their filter extract. This will contain a good cross section of autotrophic and heterotrophic bacteria (as well as other beneficial micro-organisms) and give your filter performance a real boost.

4. Now is the window of opportunity to remove any settled debris or silt from the Waxhaw NC pond bottom. Act before the pond's turnover and fish activity increases, mixing the sediment. Rather than using a fine mesh hand-net that will do a good job a stirring up the silt, use a pond-vac.

Did you know that we offer Koi a low protein diet in spring (and autumn) for the pond's health just as much as the koi's. Koi could quite easily be offered a high protein food in spring as it would not do them any harm, however, the elevated levels of waste produced from feeding such a rich diet would soon lead to a water quality problem - and a koi health problem. We feed koi a lower protein diet because it is better for the fish and the filter.

Danger Signs.

Koi emerge in spring with imperfections/sores on their body, or damaged extremities to fins and tail. These symptoms must be treated topically, backed up by a pond treatment regime.
Individual koi showing abnormal behavioral signs. Bowl these koi and check for any obvious external lesions, remembering to check the underside of the koi. Treat accordingly.
Watch out for ammonia and nitrite levels rising, as early feeding can soon overburden a seasonally immature filter. Feed and monitor water quality in tandem and educate the filter to progressively handle more waste.