''Rhodeus'' is a genus of

cyprinid Cyprinidae is a family of freshwater fish commonly called the carp or minnow family. It includes the carps, the true minnows, and relatives like the barbs and barbels. Cyprinidae is the largest and most diverse fish family and the largest ve ...

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% ...

, consisting of 23 species called bitterlings. The scientific name is derived from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

word ', meaning "

rose A rose is either a woody perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred species and tens of thousands of cultivars. They form a group of plants that can b ...

". Most species in the genus are restricted to Asia, but two species are found in Europe (''R. amarus'' and ''R. meridionalis''). Bitterlings are short-lived species, generally surviving only about five years. Their maximum size is 11 cm, but they are usually much shorter. Bitterlings inhabit slow-flowing or still waters, such as ponds, lakes, marshes, muddy and sandy pools, and river backwaters. Because they depend on freshwater mussels to reproduce, their range is restricted. Bitterlings are

omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...

, feeding on both invertebrates and plants. Bitterlings have a remarkable reproduction strategy where parents transfer responsibility for the care of their young to various species of freshwater mussels (

Unionidae The Unionidae are a family of freshwater mussels, the largest in the order Unionida, the bivalve molluscs sometimes known as river mussels, or simply as unionids. The range of distribution for this family is world-wide. It is at its most dive ...

and

Margaritiferidae Margaritiferidae is a family of medium-sized freshwater mussels, aquatic bivalve molluscs in the order Unionida. Text may have been copied from this source, which is available under Attribution 4.0 International (CC BY 4.0)licence. It is t ...

). The female extends her long

ovipositor The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typica ...

into the mantle cavity of the mussel and deposits her eggs between the gill filaments. The male then ejects his sperm into the mussel's inhalent water current and fertilization takes place within the gills of the host. The same female may use a number of mussels, and she deposits only one or two yellow, oval eggs into each. Early developmental stages are protected from predation within the body of the mussel. After 3 to 4 weeks, larvae swim away from the hosts to continue life on their own. In 1936, the bitterling was thought to respond to hormones in a pregnant woman's urine, but the work was later discredited.

Species

This genus and '' Acheilognathus'' have a convoluted taxonomic history, one being at times included in the other. They are now considered separate, but some species formerly in ''Rhodeus'' are now in ''Acheilognathus''. There are currently 23 recognized species in this genus: *'' Rhodeus albomarginatus'' F. Li & R. Arai, 2014 *''

Rhodeus amarus The European bitterling (''Rhodeus amarus'') is a temperate freshwater fish belonging to the subfamily Acheilognathinae of the family Cyprinidae. It originates in Europe, ranging from the Rhone River basin in France to the Neva River in Russia. ...

'' Bloch, 1782 (European bitterling) *'' Rhodeus amurensis'' Vronsky, 1967 *'' Rhodeus atremius'' D. S. Jordan & W. F. Thompson, 1914 (Kyushu bitterling) *'' Rhodeus colchicus'' Bogutskaya & Komlev, 2001 (Georgian bitterling) *'' Rhodeus cyanorostris'' *'' Rhodeus fangi'' C. P. Miao, 1934 *''

Rhodeus haradai ''Rhodeus haradai'' is a subtropical freshwater fish belonging to the Acheilognathinae subfamily of the family Cyprinidae. It originates in the Hainan province of China. When spawning, the females deposit their egg (biology), eggs inside bivalve ...

'' R. Arai, N. Suzuki & S. C. Shen, 1990 *'' Rhodeus laoensis'' Kottelat, A. Doi & Musikasinthorn, 1998 *'' Rhodeus meridionalis'' S. L. Karaman, 1924 *''

Rhodeus monguonensis ''Rhodeus monguonensis'' is a species of freshwater ray-finned fish in the genus ''Rhodeus''. It is endemic to China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous cou ...

'' G. L. Li, 1989 *'' Rhodeus ocellatus'' Kner, 1866 (rosy bitterling) *'' Rhodeus nigrodorsalis'' *'' Rhodeus pseudosericeus'' R. Arai, S. R. Jeon & Ueda, 2001 *'' Rhodeus rheinardti'' Tirant, 1883 *''

Rhodeus sciosemus ''Rhodeus sciosemus'' is a subtropical freshwater fish belonging to the Acheilognathinae subfamily of the family Cyprinidae. It originates in inland rivers in Japan. It was originally described as ''Acanthorhodeus sciosemus'' by Jordan & Thomps ...

'' D. S. Jordan & W. F. Thompson, 1914 *''

Rhodeus sericeus The Amur bitterling (''Rhodeus sericeus'') is a small fish of the carp family. It is sometimes just called "bitterling", which dates back to the time when the European bitterling (''Rhodeus amarus'') was still considered conspecific with ''R. ...

'' Pallas, 1776 (Amur bitterling) *''

Rhodeus shitaiensis ''Rhodeus shitaiensis'' is a species of freshwater ray-finned fish in the genus '' Rhodeus''. It is endemic to China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous co ...

'' F. Li & R. Arai, 2011 *'' Rhodeus sinensis'' Günther, 1868 (Light's bitterling) *'' Rhodeus smithii''

Regan The family name Regan, along with its cognates O'Regan, O Regan, Reagan, and O'Reagan, is an Anglicized form of the Irish surname Ó Riagáin or Ó Ríogáin, from Ua Riagáin. The meaning is likely to have originated in ancient Gaelic ''ri' ...

, 1908 *''

Rhodeus spinalis ''Rhodeus spinalis'' is a subtropical freshwater and brackish water fish belonging to the Acheilognathinae subfamily of the family Cyprinidae. It originates on Hainan Island and the Xijiang River basin in China, and may be native to portio ...

'' Ōshima, 1926 *'' Rhodeus suigensis'' T. Mori, 1935 *''

Rhodeus uyekii ''Rhodeus uyekii'' is a temperate freshwater fish belonging to the Acheilognathinae sub-family of the family Cyprinidae. It originates in inland rivers in South Korea. It was originally described as ''Pseudoperilampus uyekii'' by T. Mori in ...

'' T. Mori, 1935

Species

References

Further reading