Orochi Medaka Ricefish

Orochi Medaka Ricefish

Orochi Medaka Ricefish (Oryzias latipes) is among the most striking selectively bred varieties of Medaka — a jet-black fish in which the intense black coloration extends uniformly across the body, all fins, and even the eyes, leaving no silver, iridescence, or lighter patterning. "Orochi" is a Japanese name for the mythical eight-headed dragon, and the variety earns its dramatic name through this uncompromising, all-black appearance. Unlike more common black fish in the hobby that show dark coloration only on certain parts of the body, a true Orochi Medaka is black everywhere — the result of many generations of selective breeding to enhance and maximize melanophore (black pigment cell) coverage.

⚠ Color Maintenance — Dark Environment Required: The depth of the Orochi's black coloration is not fixed — it is actively maintained by the fish's environment. Light-colored substrate, bright backgrounds, or high-intensity lighting cause the fish to pale over time as melanophores contract and redistribute. A dark substrate (black sand or dark gravel), dark background, and subdued or diffused lighting are genuinely necessary to maintain the full depth of black coloration this variety is selected for — not just aesthetically preferable.

Feeding & Care Tip: Feed a varied omnivore diet with both protein and plant matter — Sera Vipan Tropical Flakes crushed to an appropriate size make a good daily staple. Supplement 2–3× per week with Hikari Frozen or Freeze-Dried Baby Brine Shrimp or Hikari Frozen Daphnia for protein. Medaka are surface and mid-water feeders, so floating and slow-sinking foods work better than heavy sinking pellets. Feed small amounts 2–3 times daily — medaka have small mouths and stomachs and do better with frequent small meals than infrequent large ones. For fry, Sera Micron Fry Food is an ideal first food.

Medaka Ricefish are native to the rice paddies, shallow ponds, and slow-moving streams of Japan and East Asia — a subtemperate environment that makes this species genuinely unusual: it thrives at temperatures well below what most tropical aquarium fish require, and can often be kept without a heater in a cool room. It is one of the most cold-tolerant aquarium fish available, surviving temporary drops to near-freezing in outdoor ponds, though the ideal aquarium range for consistent health and activity is cooler than most tropical species. Orochi Medaka are hardy, adaptable, and breed readily in freshwater — females carry sticky egg clusters near the anal fin before depositing them on plants or spawning mops, and eggs hatch in 10–14 days depending on temperature.

Keep in groups of 6 or more — Orochi Medaka are a schooling species that are more confident, active, and visible in a proper group than kept singly or in pairs. They are peaceful with other small, non-aggressive fish and with adult dwarf shrimp, though they may pick at very small shrimp fry. Dense planting and floating plants with long roots (such as water lettuce or Amazon frogbit) provide both cover and natural spawning sites. Flow should be gentle — these are fish of still to very slow-moving water and strong current stresses them.

A tight-fitting lid is important — Medaka are active surface swimmers and will jump, particularly when startled. A mature, well-planted tank brings out the best behavior and color in this variety; they are less active and more hidden in sparse, bright, or unstable setups.

Care & Ideal Parameters