Page 331 - Encyclopedia of Aquarium and Pond Fish, 3rd Edition

BREEDING 329

COMMERCIAL KOI PRODUCTION
Today, commercial koi breeding practices vary widely from country to The fry hatch after five days and become free-swimming within a further
country, but in Japan they still follow fairly traditional lines. A female is 24 hours. They are then moved to a rearing pond. Successful koi breeding
selected for breeding when she is about five years old. She is kept with relies on ruthless assessment, and this process begins when the fish are
two or three males in a large net, on the bottom of which is an artificial barely a month old. They are carefully caught and examined, and any
medium known as spawning grass. Using multiple males ensures that as showing deformities or poor markings are culled, leaving the remaining
many of her eggs are fertilized as possible. This is vital, since only about koi more growing space in the pond. Two further culls are carried out
one in 70,000 fry will be of the highest quality. When the koi have over the summer. In early fall, the koi are assessed for a final time. The
spawned, the eggs are moved to a well-oxygenated hatching pond, which best specimens are kept at the farm as breeding stock and taken indoors
is medicated to minimize the risk of the eggs being attacked by fungus. to overwinter, while the remainder of the group are sold.

The selection process is a daunting Koi fry are reared in large, muddy ponds, which are Bringing the breeding stock indoors
task, due to the vast numbers of fish conditioned in advance with chicken manure to encourage Large koi are during winter helps to maintain their
involved. It takes years of experience the growth of microscopic infusoria for the fry to eat. caught in strong, appetites and growth rates. Koi must
deep nets to
to identify the best specimens at Plenty of food and spacious surroundings ensure that minimize the be touched only with wet hands, to
such an early stage of development. the young koi develop to their maximum potential. risk of injury protect their delicate mucus coating.

SHOWING KOI
Koi shows are great occasions for breeders, dealers, and hobbyists alike.
The fish are exhibited in different size categories. The smallest category
typically includes fish up to 8 in (20 cm) long, and the largest includes
those in excess of 32 in (80 cm). All the fish are displayed in the same
blue vats, to make the task of judging easier, and measured with a
floating scale to ensure that they are of the correct size. The judges do
not compare the fish directly with each other but instead assess them
against what is considered the ideal for that particular koi variety. Color,
patterning, body shape, skin quality, and even swimming action are all
taken into account. Great care is needed when transporting koi to and
from shows, since any blemish, such as a split fin or abnormal reddening
of the skin due to stress, can ruin a koi’s chances of success.

Judges consider the qualities of two koi at a Japanese show. Koi are bred
to be viewed primarily from above, so the fish are not usually caught and
examined as part of the judging process but simply assessed in their vats.

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