Matsuba
Matsuba, or Matsubagoi, are most commonly bred as metallic fish, and benched in Hikarimono. The reticulated scalation is counted as only one color by the Japanese. However, matt-scaled Matsubagoi go into Kawarimono. These are understated Koi and quite rare, although Aka Matsuba are sometimes seen entered in the Jumbo class; being a very early variety, they grow large. Aka Matsuba are red Koi with dark scale reticulation, and of Asagi lineage. However, the head should be red, rather than white. Any patches of blue and the fish is classed as an Asagi.
Ki Matsuba are most often seen in their Doitsu form, and resemble a Shusui in which the red and blue skin is replaced by yellow. The white equivalent is the rare Shiro Matsuba.
Midorigoi are green Doitsu Koi, the only variety to show this color. The actual shade is more of a translucent greenish yellow, while the mirror scales can be black or silver. These fish originally resulted from a cross between a Shusui and a Yamabuki Ogon. The only variety likely to be confused with them is the Doitsu Ki Matsuba. Crossings between Shusui and Midorigoi occasionally throw up the rare Enyu, a purplish Koi with hi markings