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Orochi Medaka (オロチメダカ)

A jet-black legend of the medaka world

Overview

The Orochi Medaka (オロチメダカ) is a remarkable ornamental strain known for its intensely deep black coloration that remains unchanged regardless of background or lighting. Named after the legendary Japanese serpent “Yamata no Orochi”, this variety symbolizes strength, mystery, and elegance. It is widely considered one of the darkest and most stable black medaka strains ever developed.

Origin and Development

• Release Year: 2016
• Breeder (作出者): Masaaki Tanikuni (谷国 正明)
• Affiliation: Asuka Medaka (明日香メダカ)
• Region: Nara Prefecture, Japan

Before Orochi, black medaka lines such as Ogawa Black and Pure Black Medaka would often fade in color when kept in white or bright containers due to background adaptation — a common natural response in medaka. The breakthrough with Orochi was its ability to retain its deep black hue regardless of environment, thanks to the absence of background adaptation response. This marked a major milestone in medaka breeding history.

Key Features

• Consistent Black Coloration:
  Orochi Medaka remains deeply black whether placed in white, black, or transparent containers — a trait that sets it apart from all previous black medaka strains.
• Transparent Scales (Clear Scale Type):
  Though the body is completely pigmented, the eyes reveal its transparent scale trait, allowing breeders to categorize it as a “clear scale black” type.
• High Fixation Rate:
  Most individuals show strong black coverage. However, some may exhibit slightly grayish tones or partial transparency near the abdomen, so ongoing selective breeding is important to maintain quality.

Care Recommendations

• Viewing Style:
  Orochi Medaka is striking when viewed both from above and from the side. Its solid black body creates a dramatic contrast against any background.
• Tank & Container:
  Housing in white or light-colored containers is especially recommended to enhance the visual impact of its black body.
• Feeding:
  No special diet required — standard medaka food is sufficient.

Notable Variants and Crosses

• Black Diamond (ブラックダイヤ):
  A luminous variety born by crossing Orochi Medaka with Hoshikawa Medaka, resulting in a black base body covered with shimmering lame (iridescent scales).
• Yamata no Orochi (ヤマタノオロチ):
  Incorporates the Swallow trait, producing long-finned, flowing individuals with the same deep black base.
• Ogawa Black (小川ブラック):
  A 2009 variety by breeder Ogawa, considered a precursor to the Orochi line. While notable in its time, it doesn’t maintain black coloration as reliably in bright environments.

Conclusion

The Orochi Medaka is a true icon in the medaka world. With its unwavering black tone and symbolic naming, it continues to be a favorite for breeders and hobbyists alike. Its development was a significant breakthrough, offering a stable and dramatic aesthetic option for both pond and aquarium settings. Whether you’re captivated by its mythical name or mesmerized by its visual strength, the Orochi Medaka is a must-have for serious medaka enthusiasts.

Sources / 出典:

明日香メダカ（Asuka Medaka） / 谷国 正明氏インタビュー

Aqualassic – Orochi Medaka Overview

Medaka no Yakata Blog