Asagi koi
Asagi / Shusui

Asagi

Nishikigoi Identification Guide

Discover the timeless elegance of Asagi Koi, one of the oldest varieties featuring stunning blue reticulated scales and vibrant red accents.

The Asagi is one of the most ancient and foundational varieties of Nishikigoi, tracing its lineage back over 160 years to the very origins of koi breeding in Japan. Unlike the vibrant, opaque patterns of Kohaku or Sanke, the Asagi possesses a subtle, ethereal beauty that reflects the natural aesthetics of the early Magoi. Its name literally translates to 'pale blue' or 'indigo,' which perfectly describes the net-like reticulated pattern that defines its back. This pattern, known as 'amime' or fishnet reticulation, is created by the darker centers and lighter edges of each scale, giving the fish a textured, armor-like appearance that shimmers under the water. The ideal Asagi features a clean, unblemished head of pale blue or white, contrasting sharply with the 'Hi' (red) that typically adorns the cheeks, belly, and base of the fins. Breeders and collectors alike prize the Asagi for its longevity and hardy nature, as well as the way its colors evolve over time. Achieving a perfectly balanced Asagi is notoriously difficult; the red must remain below the lateral line, and the reticulation on the back must be perfectly uniform from head to tail. In Japanese culture, the Asagi is often associated with the serenity of a clear mountain stream, embodying a sense of stoic grace. As a non-metallic variety, it relies on the depth of its blue skin rather than sheen to command attention. Watching an Asagi glide through a pond is a lesson in historical appreciation, reminding us that the complexity of modern koi varieties all began with these elegant, blue-scaled pioneers. They are often the largest fish in a pond, growing with a robust frame that carries their traditional patterns with immense dignity and presence.

Keeping Asagi koi in Southern California

Asagi, Shusui and Koromo need the same summer oxygen, shade and feeding care as every other koi (see below).

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

# Blue/grey reticulated scales (amime pattern)# Red (Hi) markings on the belly, cheeks, and fin bases# Clean, pale blue or white head# Non-metallic skin

Expert Advice

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Available Asagi

Our current hand-selected Niigata stock for this variety.

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