The koi variety system is rich and diverse. Based on characteristics like scales and patterns, they can be divided into 13 major categories and over 100 subspecies. Below are the main classifications and representative varieties:
I. Classified by Scale Type
Common Scale Type (Japanese Lineage)
Kohaku: White body with red patches, the most classic variety, including subtypes like Denko Kohaku (lightning-patterned) and Nidan Kohaku (two-stage red patches).
Taishō Sanshoku: White body with red and black patches, distinguished from Shōwa by having no black on the head and black stripes on the pectoral fins.
Shōwa Sanshoku: Black body with red and white patches, always with black on the head and sword-like black patterns on the pectoral fins. Subtypes include Tanrei Shōwa (pale black) and Hi Shōwa (crimson-accented).
Scaleless/Minimal Scale Type (German Lineage)
Doitsu Sanshoku: Scaleless skin with white base and red/black patterns.
Shūsui: A hybrid of Asagi and German carp, with deep blue backs and red patches on the abdomen.
II. Classified by Pattern Color
Monochromatic Varieties
Ogon: Entire body covered in golden scales with a metallic sheen.
Shiro Utsuri: Pure white with no (no mixed colors).
Magoi: Solid jet-black body.
Two-Color Varieties
Utsurimono (Shiro Utsuri / Hi Utsuri): Stark contrast of black & white or red & black.
Bekko: Clear, distinct boundaries between the base color and patterns.
Three-Color Varieties
Koromo Sanshoku: Red patches with a hint of blue - like (gauze-like) texture underneath.
Fuji Sanshoku: Snow-white base with silvery white (granular) patches on the head.
III. Unique Mutant Varieties
Tancho Series
Tancho Kohaku: Pure white body with a vermilion patch on the top of the head (symbolizing "good fortune").
Tancho Shōwa: Shōwa-style patterns with a red patch on the head.
Kō utsuri Line
Kin Shōwa: Shōwa Sanshoku patterns with a golden sheen.
Kage Shōwa: Patterns with soft, hazy edges like shadows.
Variant Koi
Ryūhō Koi: Bred in Taiwan, with long whiskers resembling a dragon and broad fins like a phoenix.
Kumonryū: White base with black patterns that change with the seasons.
IV. Internationally Recognized Classification (Japan’s Zen Nippon Airinkai Standard)
The full 13 categories include: Kohaku, Taishō Sanshoku, Shōwa Sanshoku, Utsurimono, Bekko, Asagi, Koromo, Variant Koi, Ogon, Hanaishiki, Kō utsuri, Kinginrin, and Tancho. Among them, Kohaku, Taishō Sanshoku, and Shōwa Sanshoku are collectively called the "San-Kei" (Three Great Families) and account for 80% of the mainstream market.