Kind of Medaka

Kind of Medaka

Japanese Medaka is called Japanese Rice Fish or Japanese Killifish, there are only two kinds of Japanese Medaka, but there are many improved varieties, which are increasing year by year. Originally, even wild species of black medaka had variations in color and shape depending on the region, but only one kind of black medaka, to be exact, only Kitanomedaka from Aomori on the Sea of Japan side of Kyoto and other southern medaka, was used as a cultivar. However, fixation of mutant species now produces various varieties. There are nearly 500 varieties in detail, and new varieties are steadily increasing every year. Here are some of them.

A list of medaka varieties can be found later in the page.

About medaka varieties

Medaka is a generic name for freshwater fish classified as the genus Medaka, and there are more than 20 medaka friends not only in Japan but also in various parts of Asia. However, medaka other than Japanese medaka are all tropical fish, and only Japanese medaka has cold resistance.

Often referred to as the "kind of medaka", this is not exactly a "kind" but a "breed". The varieties of medaka introduced here are all improved medaka with fixed mutant species except black medaka.

Medaka varieties are classified according to the visual differences shown in the following list.

  • Body color
  • Coloring
  • Body shape
  • Eyes
  • Fin shape

Medaka body color

The color of an organism's body is determined by pigment cells. Fish have five pigments, black, red, yellow, white and rainbow. The color and pattern are determined by their combination and density.
Medaka has four pigment cells: black, yellow, white and rainbow. However, albino is an individual that has no pigment or has declined.

The main body colors of medaka are black, yellow, white, blue, brown and albino.
A variety of color variations have been created by crossing medaka with these body colors.

Coloring of medaka

By crossing various variations of medaka, medaka that has a different color from the original body color has been born.
In the so-called “Hikari”, due to the mutation, the iridescent pigment reflecting the light on the edge and abdomen of the eyes moved to the back, and the back became shiny.
The ones that lose their pigment cells and see the gills are called transparent scales.
In addition, the body light is transparent throughout the body and emits light from the body.

However, for Hikari, not only the back shines, but also the body shape changes, the dorsal fin and buttocks fin have the same shape, and the tail fin has a diamond shape. The body is symmetrical around the body.
Recently, those with the characteristics of this body shape have been called “Hikari”, and whether or not the back is shining has become less important.
In addition, like Miyuki, there are those whose body is normal but whose back is very shiny. These are not called “Hikari”.
Based on the above, it can be said that it is appropriate to consider Hikari as a feature of the body, not a feature of coloring.

Medaka body shape

There are three types of medaka body types. Normal, Dharma, and Semi-Dharma.
In addition, “Hikari” introduced in the section of coloring of medaka is recently called “Hikari figure”. Therefore, it may be said that there are four body shapes of medaka.

  • 普通体型 Normal figure
    The shape of the original medaka.
  • ダルマ体型 Dharma figure
    Due to the mutation, the number of stone pillars is small, and it has a rounded body shape.
  • 半ダルマ体型 Semi-Dharma (Half-Dharma) figure
    It has an intermediate shape that is shorter than normal and longer than Dharma.
  • ヒカリ体型 Hikari figure
    The dorsal fin and buttocks fin have the same shape, and the tail fin has a diamond shape.

Eye variations

Medaka also has variations such as eye shape and color.
The main variations are listed below.

  • Panda
    The eyes are black and look like panda eyes.
  • Small eyes
    The eyes are dots and there is little eyesight.
  • Big eyes
    The eyes themselves are big.
  • Protruding eyes
    Both eyes protrude. In rare cases, one eye may protrude due to a disease such as cancer, but the Protruding eyes are due to heredity.
  • Previous eyes
    The eyes are facing diagonally forward. Looking from the front is very cute.
  • Water bubbles eyes
    There are blisters in the eyes that are filled with lymph.

Fin variations

The medaka has 5 types of 7 fins: chest, back, belly, buttocks and tail.
There are changes in the shape and length of all these fins. Below is a list of typical fin variations.

  • Long-fin
    All or some fins will be longer. Unlike swallows, the entire fin extends.
  • Swallow
    All or some fins will be longer. Unlike Long-fin, part of the fin grows like distorted hair.
  • Samurai
    Hikari body medaka back fin is divided into two.
  • No-back-fin
    As the name suggests, there is no back fin. Miyuki Medaka that has no back fins is very beautiful because the light on the back does not break up to the base of the tail.

Yokihi Medaka (楊貴妃メダカ)

 It is an orange medaka that is closer to red than Hi-medaka. The fixed period is early, many individuals are on the market and it is an easy to obtain variety.

Miyuki Medaka (幹之メダカ)

 It is a representative of the light Medaka whose back glows when exposed to light. There are various subspecies from the size and position of the lighted surface, etc. The white or blue body color is called Miyuki.

Totenko Medaka (東天光メダカ)

 Among the hikari-type medaka, those with an orange body color like Yokihi Medaka are called Totenko Medaka. In the hikari-type, the tail fins are diamond shaped, and the back fins and the buttocks fin have the same shape.

Toumeirin Medaka (Transparent-Scale Medaka : 透明鱗メダカ)

 It is a medaka with transparent scales and looks red in blood vessels. It is a kind of Yokihi, but the appearance of blood vessels is very beautiful. The shape is the same as ordinary medaka.

Black Medaka (Kuro Medaka : 黒メダカ)

 It is a wild species medaka. Although there are differences in color and shape depending on the area, we call it Kuro Medaka as a generic name for wild type medaka. It is a type that is endangered in recent years.

White Medaka (Shiro Medaka : 白メダカ)

 The whole body is a white medaka. Sometimes it may be born whitish medaka from the Yokihi medaka, but in this case the periphery of the head pink, distinctly different from the White Medaka.

Ao Medaka(Blue Medaka : 青メダカ)

 It looks grayish when viewed from above, but in a lighted tank it is a medaka that looks bluish on the entire body. It is a medaka where it is better to watch from the side in the aquarium than to watch from above.

Dharma Medaka (ダルマメダカ)

 It is a medaka with a shrunken body like goldfish. It is a deformed medaka, and it sometimes appears during breeding. It is a malformation, and its life span is short and difficult to breed.

Hatsukoi Medaka(First love Medaka : 初恋メダカ)

 It is a dahrma figure of Yokihi Medaka. It is a malformation-type medaka and occasionally appears during breeding. Individuals with beautiful body type and color will have a price of $10 or more.

Pure Black Medaka (ピュアブラックメダカ)

 It is a black medaka that is more black than Kuro Medaka. The appearance is a very strong impression.

Sansyoku Medaka (Three-Color Medaka : 三色メダカ)

 It is a red, black and white tricolor medaka. There are various three-color medaka such as transparent scale type, Miyuki type and lame type.

Kohaku Medaka (Amber Medaka : 琥珀メダカ)

 It is a beautiful medaka like a amber. In particular, the beauty of the Dharma type can be admired.

Ougon Medaka (Golden Medaka : 黄金メダカ)

 It is an expensive colored medaka called gold. Even when mixed with other species of medaka, it is a striking presence.

Pure Black Ougon Medaka (Pure Black Golden Medaka : ピュアブラック黄金メダカ

 The pure black medaka fin is golden and it is a very beautiful medaka. The appearance rate is low, and it is a medaka for advanced users.

Lame Medaka (ラメメダカ)

 It is a very beautiful medaka whose scales shine like lame. Miyuki It is a slightly unusual medaka that is lame while possessing the characteristics of medaka.

Swallow Medaka (スワローメダカ)

 It is a medaka that it's seven fins have grown like lace. It is a new ground of medaka that has changed like a tropical fish.

Sarasa Medaka (更紗メダカ)

 It is a medaka with red and white spots. The black spot of Nishiki Medaka has disappeared and it has become a clear image by having become two colors of bright red and white.

Nishiki Medaka (錦メダカ)

 It is a two-color medaka with black spots on a dark red or white ground. It is an interesting medaka in which the way of entering a black spot is different depending on the individual by the color like a colored carp.

Ryusei (Meteor : 流星)

流星メダカIt is a medaka created as a result of pursuing the beauty of Miyuki medaka. It is a very beautiful variety that you can enjoy the light of Mikiyuki without interruption.

Tenga (Milky Way : 天河)

It is a medaka with lame on Miyuki medaka without dorsal fin. It is a breed that was created by crossing a Ryusei with Lamemedaka.

Marine Blue

It is a very beautiful medaka, with the clear body and the light blue of the body outstanding.

Kuro-Miyuki Medaka (Black Miyuki Medaka : 黒幹之メダカ)

It is a medaka in which the light of the back of Miyuki Medaka is inherited in black body color. It is a high-class medaka whose back glows like golden.

Shinkai (Deep Sea : 深海)

It is a very attractive medaka whose body is blue. It is a variety removed Mikiyuki's light from Marine Blue.

Sansyoku Lame Miyuki Medaka (Three-Color Lame Miyuki Medaka : 三色ラメ幹之メダカ)

It is a three-color medaka with red, black and white colors, containing Miyuki's light and lame. It is a beautiful medaka that surpasses the colored carp.

Akari Nishiki Medaka (灯錦メダカ)

Akari Medaka added yellow to Miyuki Medaka, further added black. It is a Nishiki Medaka whose back shines like Miyuki.

Houou Medaka (Phoenix Medaka : 鳳凰メダカ)

It is a dark brown, hikari-type medaka. It is a very beautiful medaka when viewed from the side in a glass tank.


Besides the above, there are many varieties of medaka and there are more than 500 varieties. Here we introduce rare medaka.
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