The Chinese rice fish (''Oryzias sinensis'') is a species of fish in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

Oryzias ''Oryzias'' is a genus of ricefishes native to fresh and brackish water in east and south Asia. Some species are widespread and the Japanese rice fish (''O. latipes'') is commonly used in science as a model organism, while others have very smal ...

''. This freshwater fish occurs in swamps, stagnant parts of streams,

rice field Wendel D. Ley Track and Holloway Field is a stadium in Houston, Texas. It is primarily used for track and field and soccer for the Rice University Owls. It is bounded by Main Street (southeast), University Boulevard (southwest), Reckling Pa ...

s and marshes, and is up to long. It was formerly considered a subspecies of the

Japanese rice fish The Japanese rice fish (''Oryzias latipes''), also known as the medaka, is a member of genus ''Oryzias'' ( ricefish), the only genus in the subfamily Oryziinae. This small (up to about ) native of East Asia is a denizen of rice paddies, marshes, ...

(''Oryzias latipes''). The natural range of the Chinese rice fish is in

East East or Orient is one of the four cardinal directions or points of the compass. It is the opposite direction from west and is the direction from which the Sun rises on the Earth. Etymology As in other languages, the word is formed from the fac ...

and

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainlan ...

, including the

Yangtze The Yangtze or Yangzi ( or ; ) is the longest river in Asia, the third-longest in the world, and the longest in the world to flow entirely within one country. It rises at Jari Hill in the Tanggula Mountains (Tibetan Plateau) and flows ...

Mekong The Mekong or Mekong River is a trans-boundary river in East Asia and Southeast Asia. It is the world's twelfth longest river and the third longest in Asia. Its estimated length is , and it drains an area of , discharging of water annual ...

, Irrawaddy,

Salween , ''Mae Nam Salawin'' ( , name_etymology = , image = Sweet_View_of_Salween_River_in_Tang_Yan_Township,_Shan_State,_Myanmar.jpg , image_size = , image_caption = Salween River in Shan State, Myanmar , map ...

, Red River and Nanpangjiang basins. It has been introduced to

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...

and

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eig ...

(in the lower Kuban drainage); also spreading in the

Azov Azov (russian: Азов), previously known as Azak, is a town in Rostov Oblast, Russia, situated on the Don River just from the Sea of Azov, which derives its name from the town. Population: History Early settlements in the vicinity The mout ...

basin and has been discovered in the Obytichna River in

Ukraine Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian inv ...

Ecological Niche

Chinese Rice Fish have been utilized in China and Asia for hundreds of years for

rice farming Rice is the seed of the grass species ''Oryza sativa'' (Asian rice) or less commonly '' Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera '' Zizania'' and '' Porteresia'', both wild and domestica ...

. This process allows the fish to provide protein to the rice, enhancing the food. It is proven that in the presence of rice fish, rice fields grow better, and the rice yield is increased by approximately 4-15%. Diet consists of both plants and animals. These omnivores consume plants, microscopic organisms including zooplankton and algae, and parts of insects. This introduces another biological role Chinese Rice fish play, controlling the pest population within the rice fields. The ideal environment for Chinese Rice Fish are inland freshwater and wetlands areas of shallow, slow moving water sources, especially those close to shorelines that contain vegetative cover. Rice paddies, ponds, and farming channels tend to harbor these ideal environments. When water temperatures cool, Chinese Rice Fish exhibit behaviors of hibernation. While there has not been much research conducted on the role of Chinese Rice Fish in the food web, they are primarily preyed on by dragonfly larvae, other fish, and birds. Most live for roughly one year in the wild, while in captivity, they can live for four years or more.

Roles as Invasive Species

Chinese Rice Fish are seen as high risk for becoming an invasive species. They were accidentally introduced to the

Yarlung Zangbo River The Yarlung Tsangpo, also called Yarlung Zangbo () is the upper stream of the Brahmaputra River located in the Tibet Autonomous Region, China. It is the longest river of Tibet and the fifth longest in China. The upper section is also called Dan ...

, where it is suggested that their small size assisted successful survival and reproduction rates.This accidental success demonstrated how they can adapt to different ecosystems. Chinese Rice fish also received a high CCA score, indicating they benefit from global warming, as warming waters will bring more waters into the appropriate range of temperatures that Chinese Rice fish need for reproduction.

Phylogeny

Originally, Chinese Rice fish (now labeled as ''Oryzias sinensis)'' were considered part of the

Japanese Rice Fish The Japanese rice fish (''Oryzias latipes''), also known as the medaka, is a member of genus ''Oryzias'' ( ricefish), the only genus in the subfamily Oryziinae. This small (up to about ) native of East Asia is a denizen of rice paddies, marshes, ...

(''Oryzias latipes)'' species. Mitochondrial data suggest that populations of rice fish found in Taiwan and the China-West Korean area have phylogenetic differences from ''latipes''. There is still difficulty distinguishing which populations of rice fish in Eastern Asia belong to which species, as they have similar functions in the food and farming industry. Chinese Rice Fish are still commonly referred to as Japanese Rice Fish. Medaka_Nomenclature

Use in Research

Chinese rice fish are noted to be

model organisms A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the working ...

. They are generally easy to raise due to their undemanding diet and habitat needs. Their short generation times and transparent eggs also make them ideal for observing.

References

Oryzias Fish of East Asia Fish of Southeast Asia Freshwater fish of China Fish described in 1989 {{Beloniformes-stub