Shiro Utsuri Koi

General information

Shiro Utsuri can grow tpo be between 28 – 40″ and require 500 gallons pond of larger. The Shiro Utsuri is a black fish with white markings, when being judged you want the black colors to be glossy sheen. Judges would look to make sure the blacks are deeps blacks and not brownish-black or gray-black in appearance.

Water chemistry in which Shiro Utsuri Koi are raised can influence how they look. Specifically the sumi (black) develops best in hard, alkaline water, but in softer, more acidic ponds it takes on a gray or blue tinge.

Koi being bred from Carp are an omnivorous fish species, who with their down turned mouths typically eat food items form the bottom of their pond, lake or river homes. However, as Koi are selectively bred in captivity and raised in well maintained ponds, they have adapted to eating food from the surface of the water and will readily consume a wide variety of commercial floating foods designed for Koi.

Feeding Koi when the water temperature is below 50°F (10°C) runs the risk of the eaten food may not be fully digested and will rot inside the gut of the fish causing illness and possibly cause the Koi to die.

Koi, just like standard Carp when bred naturally will spawn in the Spring and early Summer. Spawning is initiated by the male who will begin following the female about the pond, swimming right up behind her and nudging her repeatedly. After the female Koi is stimulated and releases her eggs, they will sink to vegetation, spawning mobs or even rocks or gravel on the bottom of the pond. The male will release sperm into the water and the eggs will become fertilized and begin developing. Although the female produces large numbers of eggs, many of the fry do not survive due to being eaten by other Koi or because they are not properly fertilized. On average if the egg survives it will hatch in around 4-7 days.

Japan, selectively bred carp