The European bitterling (''Rhodeus amarus'') is a

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

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% of li ...

belonging to the subfamily

Acheilognathinae The bitterling-like cyprinids form the cyprinid subfamily Acheilognathinae. This subfamily contains four genera, although the Khanka spiny bitterling is often placed in ''Acheilognathus'', and at least 71 described species to date. Over half of th ...

of the family

Cyprinidae 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 verte ...

. It originates in Europe, ranging from the Rhone River basin in

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

to the

Neva River The Neva (russian: Нева́, ) is a river in northwestern Russia flowing from Lake Ladoga through the western part of Leningrad Oblast (historical region of Ingria) to the Neva Bay of the Gulf of Finland. Despite its modest length of , it i ...

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

. It was originally described as ''Cyprinus amarus'' by

Marcus Elieser Bloch Marcus Elieser Bloch (1723–1799) was a German physician and naturalist who is best known for his contribution to ichthyology through his multi-volume catalog of plates illustrating the fishes of the world. Brought up in a Hebrew-speaking Jewish ...

in 1782, and has been referred to in scientific literature as ''Rhodeus sericeus amarus''. It is known simply as "the bitterling" in its native

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

, where it is the only

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of its

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Rhodeus ''Rhodeus'' is a genus of cyprinid fish, consisting of 23 species called bitterlings. The scientific name is derived from the Greek word ', meaning "rose". Most species in the genus are restricted to Asia, but two species are found in Europe ('' ...

'', and sometimes in the scientific literature, also, but this is technically wrong, being a leftover from the times when the European bitterling was united with its

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...

n relative, the

Amur bitterling 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. ...

, in ''R. sericeus''. Properly, "bitterling" can refer to any species of ''

Acheilognathus ''Acheilognathus'' is a genus of cyprinid fish native to Asia. The name is derived from the Greek ''a'', meaning "without", the Greek ''cheilos'', meaning "lip", and the Greek ''gnathos'', meaning "jaw". Morphology Fishes of this genus have l ...

'' or ''Rhodeus''. The fish reaches a size of up to . It is found among plants over

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of s ...

y and muddy bottoms in shallow waters. It feeds mainly on plants, and to a lesser extent, upon worms,

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s, and

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

larvae. This species of fish was once used for human pregnancy tests. Female specimens were injected with the

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excretion, excreted from the body through the urethra. Cel ...

of the woman to be tested. If the woman was

pregnant Pregnancy is the time during which one or more offspring develops (gestation, gestates) inside a woman, woman's uterus (womb). A multiple birth, multiple pregnancy involves more than one offspring, such as with twins. Pregnancy usually occur ...

, the hormones in the urine would cause the fish's

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 typical ...

s to protrude. The fish spawns in clear, slow-running or still water, often with a muddy bottom. The female deposits her eggs inside freshwater

mussel Mussel () is the common name used for members of several families of bivalve molluscs, from saltwater and Freshwater bivalve, freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other ...

s. The male sheds his

sperm Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, whi ...

into the inhalent current of the respiring mussel and thereby fertilizes the eggs. The young hatch and remain protected within the mussel for about a month, eventually leaving the mussel as actively swimming larvae. Both sexes reach sexual maturity in 1 year, at a length of .

References

{{Authority control

European bitterling 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 Russi ...

Freshwater fish of Europe