Japanese Rice Fish


There are over 5000 local names for Japanese rice fish. They are very familiar to Japanese, often mentioned in nursery songs. Until recently, it was said that Japanese rice fish was the only kind of species in Japan. However, in 2011, Japanese rice fish found in northern Japan got classified as Kitano Medaka (North Japanese rice fish) and all other Japanese rice fish got classified as MinamiMedaka (South Japanese rice fish).

These two types live in mild current areas like ponds, lakes, paddy fields, industrial waters, and downstream area. They can grow up to be 4 cm in length.

They are omnivorous and eat planktons and small insects. Due to the decreasing paddy fields, its numbers began to decrease around the 1980s. In 1999, it was listed on the Red List by the Ministry of Environment and in 2003, it was classified as endangered species.

On the tank to your left is a MinamiMedaka, which is found south of Iwate on the Pacific side and various other locations south of Kyoto on the Sea of Japan side. In Kagoshima, only MinamiMedaka can be spotted. It is said that the MinamiMedaka of OsumiPeninsula and SatsumaPeninsula have different genetics.

“Himedaka”, a variety of Japanese rice fish, are sold at your local pet shops. Their body is red and has been popular aquarium fish since the Edo period. Since they are different from wild Japanese rice fish, it’s important that you do not release them in the wild.