Koi Breed Spotlight: Shusui

Shusui is a Japanese term which translates into “autumn sky,” and it is also used to describe a specific breed of koi fish. It was first created by Kichigoro Akiyama in 1912 while he worked at Tokyo Fisheries College as a teacher. Below is a detailed overview of this fish and its characteristics.

Appearance

This fish is related to the Asagi and shares many of its visual attributes. However, it is distinct in that it has a back which is clear blue in color, with a collection of scales which are large and dark blue that are perfectly arranged in a hi pattern which is complementary.

The blue colored ground should be reminiscent of the autumn sky the fish is named after, but it should also display shades of royal blue or ultramarine. The fish’s head is bald with a bluish pale color and both the pattern and hue must be even from its neck to tail, and from its dorsal line until just beneath its lateral line. A paler blue will more sharply offset the hi pattern and dorsal scale, and neither the back nor head should have any blurs or spots.

Pattern

The large, dark scales which are present in the dorsal line must be conspicuous and neatly displayed. The dorsal scale should begin close to the fish’s head while extending beyond its dorsal fin until it touches the tail without having interruptions by scales which are crooked. Any Shusui which displays gray or black scale will receive a demerit. Furthermore, superfluous scales which appear singly or in clusters will also reduce its value.

The hi should display the fiery red which appears in the Asagi. However, it must be confined to the cheeks, abdomen and fin, with the only exceptions being Hana Shusui and Hi Shusui. Hi will also display prominently in the fish’s pectoral fin base, which really gives them a flamboyant appearance.

Historically speaking, the earliest Shusui specimens did not display much red, and were primarily blue in color. However, this changed by 1930 when a reddish pattern was produced by crossing back to the Asagi. Since then most Shusui have displayed a lateral red color.

Variants

Shusui is further broken down into four variants, which are Hana Shusui, Ki Shusui, Hi Shusui and Pearl Shusui. Hana Shusui display a secondary hi line pattern that extends from the lateral to dorsal lines. Ki Shusui display yellow with a blue colored back. Hi Shusui have a red colored abdomen that spreads upward to cover the entirety of their back. Pearl Shusui has fukurin on their back scales.

Occasionally you might also come across Metallic Shusui. Those that display a lateral red pattern are referred to as Kinsui, but those which do not have red coloration are named Ginsui. Shusui were developed with the goal of adding extra genetic diversity which results in beautiful lateral patterns while allowing for a sturdier body shape.