Neptune Medaka / ネプチューンメダカ – 2 Unsexed Import Fish

Neptune Medaka, known in Japanese as ネプチューンメダカ and romanized as Nepuchūn Medaka, is a modern Japanese improved medaka strain developed by Medakaya Savanna / メダカ屋サバンナ, a well-known breeder from Saitama, Japan. Japanese sources list Neptune as a 2023 strain, and it gained attention quickly because of its strong blue expression and heavy metallic lame.

The reported lineage of Neptune is:

Miyazakura / 宮桜 × Himitsu Heiki / ヒミツヘイキ × Saboten / サボテン

More specifically, Japanese hobby sources describe the cross as (Miyazakura × Himitsu Heiki) × Saboten. The Miyazakura × Himitsu Heiki base was reportedly managed as Prince, which later helped produce Neptune and other Savanna lines.

Neptune combines traits from all three parent lines. Miyazakura contributes complex color and blue lame contrast, Himitsu Heiki contributes dense, high-coverage lame, and Saboten contributes large reflective lame and fin shine. The finished Neptune expression is a blue-based, aurora-influenced lame medaka with strong metallic sparkle, blue head/body reflection, and flashes of silver, blue, and sometimes gold depending on the viewing angle.

This group shows the classic Neptune look: clean blue-silver body tone, bright reflective scales, heavy lame across the back, and a cool ocean-like shimmer. Some individuals show stronger blue shine across the head and shoulders, while others show more silver or pale gold sparkle. They look best in black or dark gray tubs, which helps tighten the blue color and bring out the metallic lame.

Because Neptune carries aurora/lame traits, offspring can show some variation. Breeders should select for strong blue head expression, dense back lame, clean body shape, and good reflective shine. Japanese sources also mention Neptune types such as standard Neptune, Golden Type, and Silver Type, so selective breeding is important if you want to keep the line leaning blue/silver.

Traits Seen in This Group

• Japanese import Neptune line
• Blue-silver metallic body
• Heavy lame sparkle across the back
• Blue shine on head and shoulder area
• Silver, blue, and subtle gold reflective scales
• Normal body type
• Clear/translucent fins
• Good top-view and side-view appeal
• Best color in dark tubs or display containers

Breeder / Project Notes

This is a great strain for collectors and breeders who like blue-based medaka with high-end lame expression. For breeding, keep the fish with the strongest blue head, cleanest silver-blue body, densest back lame, and best body shape. Cull or separate fish that are too pale, too yellow/gold, weak in lame, or lacking the Neptune blue/silver shine.

Care

Neptune Medaka are kept like other Japanese ricefish. They do well outdoors in tubs or indoors in aquariums with clean, stable water. Strong natural sunlight or bright aquarium lighting helps bring out the best blue-silver shine and lame sparkle. Use a black or dark gray container for the best color development.



Photos show the actual Neptune import group. Individual fish selected may vary.