White Koi

In the early 1800’s when the Japanese began breeding Koi from carp
mutations, one or two colors were all their were.  But, they grew
in popularity very quickly and as many people began breeding them
they began to come in greater varieties and combinations of colors
and patterns.  Koi today can be seen in a wide variety of colors
including orange, black, yellow, green and white as well as many
patterns of colors.
In order to recognize the different varieties of Koi you need to
have an understanding of the different classifications that Koi are
grouped into.  Each of the different varieties has its own
standards, but most varieties allow for variations in coloring or
patterns.  Among the varieties of Koi a couple stand out as the
most popular.  Kahaku Koi is one of the more popular as well as the
Hirarimono or Ogon variety.  The Kahaku are white with red markings
and the Hararimono are metallic and single colored.
“Hikari”, the first part of the word means metallic and “mono”
means single color.  So these Koi are a single metallic color.
The Ogon Koi are also a solid color with a very metallic appearance.
The most common colors of Ogon are yellow, also known as Yamabuki
Ogon, and white or silver known as Platinum Ogon.  In all of these
varieties th coloration should be the same from head to tail with
no variations in color.  In the Ogon Koi, large fins are desirable
because they offset the plain colored bodies.
The shiny luster of the White Koi or Platinum Ogon give the look of
a precious metal.  These beautiful fish first asppeared back in 1963,
most likely from breeding Kigoi with the grayish silver Nezu (the
Japanese word for rat or Nezumi) Ogon.  These Koi Fish are very
hardy and grow very fast.  They are great for poorly filtered or ‘
very large Koi ponds because they stand out in the murky water.
Other Ogon Koi include the Orenji, Nezu and the Fuji Koi.
In order to give them a shinier appearance the majority of the
Platinum Ogon Koi are bred with Ginrin scales.  They are distinctly
different than the Metallic Koi’s overall gleam caused by reflective
pigment of the scales, Ginrin scales sheen over all or part of their
surface and have a glimmering effect much like cut diamonds.  To
qualify for this catefgory the fish needs to have more of these
scales than one can count as the fish swim by.  About 20 of these
scales is usually the minimum accepted.
The large variety of colors of the Koi Fish is the real attraction for
pond owners to fill their ponds with Koi Fish.  Koi should always be
viewed from the top as this shows off their colors best.  Most of
the fishes pigment are on the top side of the fish. Round pools are
always used for events in Asia and the Koi are always viewed
directly from the top.
articles from http://www.raisingkoifish.com