Breeding Koi

Here is an article that gives light to breeding Koi. Owners, breeders and Koi enthusiasts must have all the necessary information and equipment like a compund light microscope before trying to breed koi for the first time.

Koi that are less than about 10 inches long are still too young and immature to be mated. Even as they mature, some females present as skinny and some males are quite large. But usually, female koi are plump because of the eggs they are carrying in their ovaries. They also have smaller pectoral fins, while males are more streamlined and shaped like torpedoes. It is also easier to identify a male from a female because they tend to have breeding tubercles on their heads and pectoral fins during the breeding season. Be careful though, these raised tubercles are often mistaken for white spots of what they call ichthyopthirius. View Koi at a larger scale using a compound light microscope.

Koi that are longer than 10 12 inches are usually mature enough to spawn spontaneously in the early summer season. A conducive water temperature of 20C will encourage koi to spawn in a flock. They will produce quite healthy offspring but their colors tend to be poor. For good quality koi breeding, the article recommends separating the parents in another pond for breeding, at a ratio of 2 to 3 males to one female. This is largely due to the fact that eggs may be eaten by other fish if they are all in same pond. Sometimes, some breeders move fry or the baby fish to a separate tank where no adults are present. The article recommends using spawning brushes for the koi to spawn on because it may be difficult to collect eggs that may be scattered all over the pond.

Breeders know that the eggs are ready to hatch when the eyes in the eggs have a certain shine. In a few hours the koi will wiggle out and break out of the egg. Hatching is quicker in higher temperatures, but at 20C it will take about 3 or 4 days. See how their eggs look like under a compound light microscope.

The fry should have an adequate oxygen supply as soon as they are hatched. This article recommends having an airstone. Usually, the fry will attach themselves to the walls of the tank for about 2 to 3 days via a sticky pad on their heads. They will then swim up to the surface for some air, which is directed to their swim bladders, this allowing them to swim around. This is the time to begin feeding them. For the first day, the article suggests feeding fry egg yolks to increase stomach girth, although this has no nutritional value for the fry. As they grow to about half an inch, they can be fed small pellets. Increase the size of the pellets as they grow. It is essential not to over feed the fry. It is also vital that the water quality is checked regularly because fry are very sensitive to high ammonia levels in the water and may quickly die if this is not taken care of properly.