A clear guide to the key terms used in Medaka keeping and buying
A Medaka breed known for its vivid vermilion-red body color. This iconic variety sparked the ornamental Medaka boom and is admired for its deep orange to red coloration. As a flagship of selectively bred Medaka, it is easy to keep even for beginners.
A Medaka breed featuring a metallic sheen (external light) along its back. It is graded by the extent of the shine, ranging from Super to Full Body. This breed is especially stunning when viewed from above.
A Medaka trait where scales display sparkling iridescence caused by clusters of iridophores. The glitter scattered across the body resembles tiny gemstones. The quantity and hue of the glitter affect an individual fish's value.
A Medaka body type with fewer vertebrae than normal, resulting in a round, compact shape. Also formally called 'shortened Medaka.' Its cute appearance is popular, but it is a weaker swimmer and somewhat harder to breed.
A Medaka trait where all fins grow longer than normal. The fish swims gracefully and is best appreciated from the side. Also known as Swallow, the dorsal, anal, and caudal fins are particularly elongated.
Water that has turned green due to the growth of phytoplankton such as chlorella. It serves as food for Medaka fry (called 'hariko') and develops naturally in outdoor setups. It significantly improves fry survival rates.
The term for newly hatched Medaka fry. At only 2–3 mm long, they are as thin as a needle. Because their mouths are extremely small, they must be fed powdered food or raised in green water.
A device or material for Medaka to attach their eggs to. Commercial sponge-type spawning mops or floating plants like water hyacinth are commonly used. They make egg collection easy and help prevent the parents from eating the eggs.
A viewing style where Medaka are admired from above. Enjoyed when keeping fish in lotus bowls or plastic tubs. Many breeds, such as Miyuki with its metallic sheen or Lame with its sparkling scales, look their best from this angle.
A viewing style where Medaka are observed from the side, typically in glass aquariums. It is preferred for evaluating breeds like Long Fin and Hikari body types, whose features stand out best from a lateral perspective.
The process of selecting individuals with desirable traits from bred Medaka. It is a crucial step for maintaining and improving breed characteristics, judged by criteria such as body color, body shape, and light expression.
The rate at which parent Medaka traits are passed on to offspring. A higher fixation rate means more fry inherit the same characteristics as the parents. Newer breeds tend to have lower rates, which are improved through successive rounds of selective breeding.