Doitsu

Doitsu Kohaku

Nishikigoi Identification Guide

Doitsu Kohaku combines the classic red and white pattern with the clean look of a scaleless body. A favorite for modern collectors.

The Doitsu Kohaku is a stunning fusion of one of the oldest koi varieties and a German influence that changed the hobby forever. "Doitsu" refers to the lineage of the German mirror carp, which was introduced to Japan in 1904. These fish were either entirely scaleless or possessed only a few large, decorative scales along the dorsal line or lateral line. When this trait was bred into the Kohaku—the classic red-and-white variety—the result was the Doitsu Kohaku. The absence of scales creates a unique canvas for the red (Beni) patterns. On a standard scaled Kohaku, the edges of the pattern (the kiwa) are often slightly blurred or "stepped" by the scales. On a Doitsu Kohaku, however, the boundaries between the snowy white skin and the deep red markings can be incredibly sharp and clean, looking almost as if they were painted onto the fish. This "clean" look is highly prized by modern collectors who appreciate bold, graphic aesthetics. The skin of a high-quality Doitsu Kohaku has a smooth, leathery, and often glowing texture that differs significantly from the shimmer of a scaled fish. Because there are no scales to distract the eye, the quality of the skin and the intensity of the color are under even greater scrutiny. Any blemish, freckle, or unevenness in the white base is immediately visible. The most desirable koi feature large, well-balanced patches of red that do not wrap too far below the lateral line. While Doitsu koi are sometimes thought to grow slightly slower or stay smaller than their scaled counterparts, many modern breeders have produced Doitsu Kohaku that rival any other variety in size and body conformation. They are hardy and active fish, bringing a vibrant and modern energy to the pond. For the hobbyist, the Doitsu Kohaku represents the perfect marriage of traditional Japanese color theory and unique European morphology, resulting in a fish that is both timeless and strikingly contemporary.

Keeping Doitsu Kohaku koi in Southern California

The white skin (shiroji) is the part of these koi most likely to burn in strong sun. The typical sign is a red rash on the back, and shading the pond for at least two weeks lets it settle.

The red (hi) depends on carotenoids in the diet, and warm, stable water helps koi absorb them. Red that fades after stress often does not come back, so heat stress is worth avoiding.

Some sun is good for colour. Partial shade suits these fish better than full shade. This applies to doitsu (scaleless) Kohaku and Sanke too: a breeder's documented sunburn case found no difference between scaleless and fully scaled fish.

Summer care for every koi in SoCal
  • Warm water holds less oxygen, yet koi need more oxygen as the water warms. That makes summer the season when oxygen runs shortest.
  • Oxygen is usually lowest around dawn, because plants and algae use it up overnight. In summer, keep air stones, waterfalls or fountains running day and night.
  • When oxygen runs short, large fish are often the first affected. The bigger and faster-growing your koi, the more aeration matters.
  • Published "ideal" ranges vary between sources, from about 59–77°F to 68–78°F. Most sources treat the low-to-mid 80s °F as the point where you should cut feeding, add shade and add aeration.
  • At about 82°F and above, feed less than usual. Koi can lose their appetite at 86°F and above, so offer small amounts of an easily digested food and remove anything left uneaten.
  • Shade part of the pond, but not all of it, from the afternoon sun. A shade sail, pergola or floating plants will do. Don't enclose the surface so tightly that air can't move over it.
  • Inland SoCal is much hotter than the coast. NOAA's 1991–2020 normals give an average July–August afternoon high of about 95–97°F in Riverside, 83–85°F in Santa Ana and 75–77°F at LAX (air temperature). Inland ponds therefore need the heat measures above sooner and for longer.

Key Traits

# Scaleless or mirror scales# White base with red patterns# Clean, sharp color boundaries

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