It
is very difficult to breed good quality Nishikigoi. Professional Koi
breeders even find it hard. Hobbyists still try Koi breeding to see the
results they get.
The most important thing is to choose good quality parents with
excellent blood lines. This is critical. Unknown blood lines and
background may cause an undesirable variety of babies. For instance,
from a Kohaku parent there might be many different types of Koi such as
Taisho-Sanshoku or Showa-Sanshoku, even Ogons and Asagis. Since there is
no such thing as a pure blood line, there is always a chance the babies
could be drastically different from the parents.
If planning to spawn Kohaku, Taisho-Sanshoku or some other popular
breed of fish, make sure the parent Koi have snow white areas, bright
colors, even colors and sharp edges on the patterns. Balance and
formation of pattern on the parent Koi is not an important factor. The
resulting patterns on babies is a matter of chance and cannot be
planned.
The age of the female should be three to ten years. If the female is
too small, her eggs will be small and cause premature birth and most of
the babies will die. For the most effective spawning, the male should be
three years or older, if any younger he is probably unable to produce
sperm effectively.
Some well known breeders in Japan will breed with only one male and one
female, however, this can develop into a lengthy process since it is
difficult to select both fish in the peak of spawning condition. If the
breeding is only a part of your hobby, one female to three males is
suggested. If the mating is a failure the first time, the male partners
should be changed. Also, if the female fails to produce eggs, there is a
possibility she has a stomach tumor and should be exchanged for another
female with eggs. The major classifications of Koi should not be mixed
forbreeding. For instance, if Kohaku breeding is being tried both male
and female parents should be Kohaku.
After selecting the parents a decision must be made concerning the
container for the spawning. This should be sturdy and smooth as, in the
process of spawning, the Koi will move around a lot and often rub up
against the sides of the tank. If it is rough, they will injure
themselves. The best type container is a tank 6 to 8 feet in diameter
and three to four feet deep. A large show tank is a good choice. Make
sure adequate aeration is available as the fish will be extremely active
and use large amounts of oxygen.
In Niigata spawning does not start until late May or early June
because of the cold temperatures. In California and the southern areas
of Japan the spawning season starts much earlier, around the beginning
of March and early April.
To induce the female to lay eggs there must be a soft and stringy
media on which she can deposit them. Typically, items like willow tree
branches, water hyacinth, a clean mop head or long stringy algae are
used. Most professional Koi breeders use a specially made fiber but,
whatever the material, it must be free from disease, parasites, and
chemicals.
Another method of spawning applies artificial techniques. This is
done by squeezing the eggs out of the female and spraying the male sperm
on the eggs. The eggs are then mixed with the sperm and placed into a
special hatching tank This is not recommended for amateurs as it can
cause injuries to the Koi.
In order for successful spawning to take place the daytime
temperature must be above 75 degrees. Many times a female will lay eggs
because the pond is shallow and cannot maintain an even temperature. The
change in temperature between night and day triggers the fish's natural
response to spawn. However, if the pond is deep and the temperature
stays even the fish will not spawn unless induced.
Setup the spawning tank early in the morning so the water has a
chance to warm up before cooling down at night. A day must be picked
when it's obvious the temperature will be over 75 degrees and will stay
this way for a couple days. Make sure the spawning materials and
aeration systems are ready and installed in the tank. The early
afternoon is the best time to release the spawning pair into the tank as
they need to adjust to the water temperature. To do this properly, put
the fish in a plastic bag with water and oxygen and float it in the tank
for at least fifteen minutes then release the fish. Because fish tend to
jump during spawning, the tank shoud be covered; such as with tautly
secured shade cloth, netting or even a heavy board. The spawning will
start at about 4:00 a.m. next morning and continue for two to three
hours.
An additional tank, with water at exactly the same temperature as the
main tank, should be ready for the fertilized eggs. (A variation of just
a few degrees is sufficient to kill the eggs). These should be removed
from the spawning tank as soon as the parents have finished their
activity. The water in the spawning tank will be white, smelly and soon
become rotten because only a small portion of the sperm, sprayed by the
male, is adhering to the eggs, the rest is distributed in the water. The
parents must also be removed and, if possible, the female placed in a
separate tank to allow her time to recover. Finally remove any eggs
remaining and place them with the others in the rearing tank.
The hatching tank should be placed in an area that does not show a
temperature fluctuation of more than five degrees day or night. The eggs
will die if the temperature changes even 10 degrees in a twenty four
hour period. The average sized female will lay between 200,000 to
400,000 eggs. An attempt should not be made to save all these eggs
because the hatching tank space is limited. They will not all hatch if
the tank is overstocked.
Within four to seven days the eggs will start to hatch. This will
vary dependent on water temperature. Warmer water will accelerate the
cyde and soon the baby Koi will start to swim. They can survive for a
few days on their yolk sack but after that is depleted, they will have
to be fed. The best food for them is microscopic animals, but if these
are not available they can survive on very small particles of dried food
such as powdered milk They will eat continuously throughout the day, and
must be fed every hour. Be cautious to feed only tiny amounts of food
because any leftovers will become rotten and kill them all. In about two
weeks, they should be moved to a larger pond for faster growth, still
feeding all the time.
The combination of feeding and culling is the most important feature
in Koi breeding. Within the first month, the first culling should take
place. Eliminate those with deformed bodies, single colors (if raising
Koi with pattern), and those that are unusually large. This type of Koi
is called "Tobi" and they usually do not have good patterns plus, they
eat the smaller ones and these smaller fish, very often, have the better
patterns. Professional Koi breeders usually save only about 10% of their
hatching. After four months most professional breeders will have grown
their Koi to about 5 to 6 inches.
-----------
After nearly three
decades as a Koi dealer,
Grant
is now sharing his knowledge through his
California Koi Seminar; 510.881.8629.
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