Not to be confused with Rhodeus amurensis

Rhodeus amurensis

Rhodeus amurensis is a temperate freshwater fish belonging to the Acheilognathinae sub-family of the Cyprinidae family. It originates in the Amur River and Lake Khanka in Asia, and is found in China and Russia. It was originally described as Pseudoperilampus lighti amurensis by B.B...

, whose scientific name literally means "Amur bitterling".

The Amur Bitterling, Rhodeus sericeus, is a small fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate 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...

 of the carp family. It is sometimes just called "bitterling", but this is wrong: for one thing, it dates back to the time when the European Bitterling (Rhodeus amarus

Rhodeus amarus

The European Bitterling, Rhodeus amarus, is a temperate freshwater fish belonging to the Acheilognathinae sub-family of the Cyprinidae family. It originates in Europe, ranging from the Rhone River basin in France to the Neva River in Russia...

) was still considered conspecific with R. sericeus, for another, "bitterling" properly refers to any species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 in entire genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Rhodeus

Rhodeus

Rhodeus is a genus of cyprinid fish, consisting of 21 species called bitterlings. The scientific name is derived from the Greek word rhodeos, meaning "rose"....

. The Amur Bitterling is found in Siberia

Siberia

Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

, while the European Bitterling is found from European Russia

European Russia

European Russia refers to the western areas of Russia that lie within Europe, comprising roughly 3,960,000 square kilometres , larger in area than India, and spanning across 40% of Europe. Its eastern border is defined by the Ural Mountains and in the south it is defined by the border with...

 westwards.

Mussel

Mussel

The common name mussel is used for members of several families of clams or bivalvia mollusca, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.The...

s form an essential part of its reproductive system, with bitterling eggs being laid inside them. Long thought to be symbiotic with the mussels (whose larval phase attaches to fish gills during development), recent research has indicated they are in fact parasitic, with co-evolution being seen in Chinese bitterling and mussel species.

Bitterlings usually reside in areas with dense plant growth. They are a hardy fish, and can survive in water that is not very well oxygenated. They grow to be 3-4 in. long at most. The bitterling's diet consists of plant material and small larvae of insects.

Colour Variation

There are 'transparent' scale variants of bitterlings, though not common, if exploited in the aquarium trade.

For photos of transparent variants of bitterlings, please see:
http://www.jstage.jst.go.jp/article/zsj/15/3/425/_pdf