Orochi medaka.What are the characteristics of the Orochi medaka? Here, we’ll explain their care, breeding, fixation rate, and price!

What are the characteristics of the Orochi medaka? Here, we explain their care, breeding, fixation rate, and price.

Characteristics of the Orochi Medaka

The Orochi medaka was developed in 2016 by Masahiro Taniguni (Asuka Medaka). The most distinctive feature is that its entire body is jet black, from head to tail.

Before the Orochi medaka was created, there were already fully black medaka fish, but the Orochi medaka remains completely black in any environment.

Medaka generally change color based on the background. For instance, they get darker in black containers and lighter in white containers. As a result, even black medaka lose their color when placed in a white container.

However, the Orochi medaka does not exhibit this reaction and remains pitch black, even in a white container. This unique feature made it famous after its creation, and it remains a popular, recognizable medaka for being completely black.

Orochi Medaka Care

Caring for the Orochi medaka is easy. Feed them daily and change their water regularly, maintaining a density of about 1 liter per fish. They can be easily kept both indoors and outdoors.

However, Orochi fry are said to be a bit weaker compared to those of other varieties like the Yōkihi or Miyuki medaka.

Still, they are easier to care for and breed in greater numbers compared to other medaka. My family keeps hundreds of them, and we find them more manageable than standard medaka.

Orochi Medaka Breeding

The Orochi medaka lays many eggs, making it an excellent choice for beginners.

Fixation Rate of Orochi Medaka

The Orochi medaka appears to have a high fixation rate due to its entirely black coloration. However, **it actually has a surprisingly low fixation rate.**
While you won’t find completely different colors, many offspring are born with lighter bodies or white bellies, even among Orochi parents. Additionally, some offspring inherit the background color response, meaning their color fades in white containers. Some breeders use white containers specifically to weed out the lighter individuals.

Compared to other strains like the Yōkihi or Miyuki, the Orochi medaka has a lower fixation rate. Even the Black Diamond has a higher fixation rate than the Orochi. Most Orochi fish that seem black actually have transparent lower bodies.

Therefore, truly jet-black Orochi are found in fewer than one in ten individuals.

Since fully black Orochi parents are more likely to produce black offspring, lineage is important in breeding. Careless breeding quickly dilutes their color, making it difficult to maintain the lineage.

Though it seems simple, the selective breeding of Orochi medaka is deep and intricate.

Orochi Medaka Derivative Varieties

Let’s explore some derivative varieties.

Orochi Daruma

Orochi Daruma
The Orochi Daruma has a Daruma body shape. Among the many Daruma medaka types, it’s highly popular and commands high prices online. They are also very hardy, making them suitable for beginners.

What Is a Daruma Medaka?


Satan is a long-finned variety of Orochi, with some individuals showing red fins. Highly popular, it is one of the most famous long-finned medaka.


Kaiji is an enhanced jet-black medaka developed by Asuka Medaka from the Orochi. It features yellow fins alongside its dark body. Popular but rarely available, it’s traded at high prices. Purebred Kaiji are called “Kaishi.”

Black Diamond

The Black Diamond, developed in 2018, is a hybrid between the Orochi and the Hoshikawa (metallic rami Miyuki). It has a jet-black body with shiny specks on the sides. Cloud Gray Diamond is a refined version featuring specks on the back.

Orochi Price and Availability

The Orochi is very popular and is widely available at medaka shops nationwide, as well as home improvement stores.
Because it’s mass-produced, its price is relatively low, ranging from around 1,000 yen per pair. At discount shops like Kanedai, they’re sold individually for a few hundred yen.

However, high-grade, fully black Orochi are rare and not widely available.

These high-quality individuals are often sold for several thousand yen per pair.


The Orochi is a jet-black medaka that has remained popular for over five years since its development. Despite its low price, it has a surprisingly low fixation rate. Nevertheless, it’s still an easy breed for beginners to care for. Give it a try!


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