The
Legendary, Long-Living Koi
Koi are tropical freshwater fish that
belong to the carp family. In fact, today's beautiful and
world-renowned koi were developed from common food carp by
fish farmers in Japan over 200 years ago by selectively
breeding the occasional fish found with some color or pattern
on it. Today koi have become popular just about everywhere
and are bred in every country. Currently, they are considered
to be the most popular and most highly prized freshwater
ornamental pond fish.
Koi and carp have always been very popular in Japan and
China, and in most parts of Asia. Koi, and its direct
ancestor the carp, have long been the stuff of legend in this
part of the world. To the Japanese, carp and koi
traditionally embody strength, courage and determination. The
Chinese call koi the king of freshwater fish, and regard it
as a symbol of good fortune and celebration. Koi are often
referred to as "living jewels" or "swimming flowers" because
of their tremendous color and color variations. All koi have
similarly shaped bodies and fins, but they come in a variety
of different colors and patterns such as gold, silver,
orange, red, blue, black, white, and all kinds of
combinations of these colors. All koi also come with adorable
whiskers on their faces, called barbels.
Koi can grow up to 3 feet (36 inches) in length and can weigh
over 5 pounds each! The growth rate and final size of your koi will also depend on water quality and conditions, feeding methods, and the size of the pond or how crowded the pool is. With optimum conditions, the average growth rate for a healthy koi is 2 to 4 inches at the end of the first year, 6 to 8 inches at the end of the second year, and 10 to 12 inches at the end of the third year. After the third year, the growth pattern slows down as the koi nears its maximum length.
Koi are very hardy and are fairly easy to keep, and also have
a pretty long lifespan. Most koi can live at least 25 to 35
years, and with good water conditions and proper care, 50 to
100 years would not be unusual. In Japan, koi are frequently
passed on to the next generation. The oldest known specimen,
a red female named Hanako, was owned by Nagoya University
President Komei Koshihara. Though Hanako died in 1977, a
microscopic examination of one of her scales proved that she
was born 226 years before her death in 1977 - she was born a
few years before the United States made its debut as a
nation!
To have the best quality koi that look the best and that are
disease free, proper care is essential. Having adequate pond
space is a very important part of this care. In fact, pond
size is the main factor in determining how many koi you can
keep and the quality of your koi. You can try to put half a
dozen koi in 1000 gallons, but the koi will probably not grow
very large or look very good. As a rule of thumb, every full
size koi should have about 500 gallons to itself.
The other reason for having adequate pond space is that the
smaller or more overcrowded a pond (or an aquarium) is, the
lower the quality of the water. Overcrowding koi in a pond
will contribute to fish stress, and greater potential for
parasitic diseases and bacterial infections. Having adequate
space in the pond will help the koi stay healthy and live
long. The pond should also be deep enough, at least 3 feet
deep. This will keep your pond cooler in the summer months,
warmer in the winter months, and keep predators like raccoons
and herons from eating your fish.
In the old days back in Japan, these gorgeous creatures were
housed in lushly landscaped outdoor fish ponds. The ponds
were constructed to provide adequate oxygenation and had a
large turnover of water to ensure high water quality and
filtration. With a little bit of energy and time, you can
also create such an environment for your koi, or at least get
pretty close to it. You can rely on either natural methods,
mechanical methods, or a combination of both to achieve a
healthy pond with proper aeration and filtration.
The natural method usually consists of planting some water
plants in the pond to provide sufficient oxygenation and
aeration for the fish, and adding a few scavengers such as
snails and catfish into the pond for cleaning up wastes from
the bottom of the pond. In addition to providing oxygenation
and aeration, water plants also serve to further beautify
your pond, help keep the water clear, and help reduce the
growth of algae that can be unsightly and consume too many
nutrients from the water.
If you find that your pond is not being kept clean and clear
enough by natural methods, or if you plan to keep a lot of
koi in the pond, you may want to use mechanical methods or a
combination of natural and mechanical methods for the
aeration and filtration of your pond. You would also probably
need to use mechanical methods for aeration and filtration if
you are keeping your koi in an aquarium, though aquarium use
is not recommended for koi unless the aquarium is of a very
good size. A good pump and filter system will filter the
pond's (or aquarium's) entire volume every couple of hours,
removing solid and chemical waste from your pond pretty much
completely.
You can get filters that come with aerators built into them.
These filters will return the water to the pond by a
waterfall or fountain, which not only looks very nice but
also aerates the pond extremely well. Another type of popular
filter is the biological filter, which is a container that is
usually filled with a medium on which bacteria will grow, and
they would consume most of the waste from the water.
Whichever filter you use, you should clean it at least twice
a year to keep it working properly and efficiently.
With sufficient natural and/or mechanical aeration and
filtration, cleaning or changing the pond water once a year
in the early spring should be sufficient. However, if you
notice your pond getting pretty dirty and overgrown with
algae, or if you suspect chemical pollution, then you might
want to change the water. In that case, change 20% of the
water in your pond once a week or so for a few weeks. This
simply means removing about 20% of the old water from your
pond and replacing it with fresh tap water from the faucet.
Avoid changing all the water at once. Scooping out leaves and
other debris from the pond regularly using a net is another
easy way to help keep the water clean and clear.
Overall, koi are remarkably hardy and healthy fish, much more
so than even goldfish or other tropical fish. Koi can
withstand a wide range of temperatures. Healthy koi can even
survive under the ice in extreme cold as long as the water
does not freeze solid. They will not move around or eat much
if the pond water is very cold, basically hibernating.
Needless to say, koi generally do not need heating. Of
course, for optimum health and comfort of the fish, it is
recommended that you avoid huge fluctuations in temperature
and pH of the water, and perhaps use some heating during the
winter months. As for food, feeding koi once or twice a day
is good. There are a variety of pellet fish foods that are
specially designed for koi. Koi can also be fed dried or
fresh shrimp, lettuce, cooked rice or cooked oats.
Keeping koi requires some space and work, but raising them is
a very fascinating and rewarding hobby. Their beauty, fame,
hardiness, and longevity make them well worth it. For the
avid koi enthusiast, there are koi shows in which koi compete
according to their size and class, often for huge prizes.
There are also hundreds of koi clubs throughout the U.S. and
the rest of the world. If you have any questions regarding
koi fish, just ask us and we will help you any way we can.
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