Rhodeus amarus

European Bitterling
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cypriniformes
Family:	Cyprinidae
Genus:	Rhodeus
Species:	R. amarus
Binomial name
Rhodeus amarus (Bloch, 1782)

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. It was originally described as Cyprinus amarus by Marcus Elieser Bloch in 1782, and has been referred to in scientific literature as Rhodeus sericeus amarus^[1]. It is known simply as "the bitterling" in its native range, where it is the only species of its genus Rhodeus, and sometimes in the scientific literature also. But this is technically wrong, being a leftover from the times where the European Bitterling was united with its Siberian relative, the Amur Bitterling, in R. sericeus. Properly, "bitterling" can refer to any species of Rhodeus.

The fish reaches a size of up to 10 centimetres (4 in). It is found among plants over sandy and muddy bottoms in shallow waters. It feeds mainly on plants, and to a lesser extent upon worms, crustaceans, and insect larvae.^[1]

This species of fish was once used for human pregnancy tests. Female specimens were injected with the urine of the woman to be tested. If the woman was pregnant, the hormones in the urine would cause the fish's ovipositors to protrude.^[1]

The fish spawns in clear, slow-running or still water, often with a muddy bottom. The female deposits her eggs inside freshwater mussels. The male sheds his sperm into the inhalent current of the respiring mussel and thereby fertilizes the eggs. The young hatch and remain protected within the mussel for approximately one month, eventually leaving the mussel as actively swimming larvae.^[1] Both sexes reach sexual maturity in 1 year, at a length of 30 to 35 millimetres (1.1 to 1.4 in).^[2]

References

1. ^ ^{a b c d} Froese, Rainer, and Daniel Pauly, eds. (2007). "Rhodeus amarus" in FishBase. February 2007 version.
2. ^ Tarkan, Ali Serhan; Özcan Gaygusuz, Çiğdem Gürsoy, Hasan Acıpınar (2005). "Life History Pattern of a Eurasian Cyprinid, Rhodeus amarus, in a Large Drinking-Water System (Ömerli Dam Lake-Istanbul, Turkey)" (PDF). J. Black Sea/Mediterranean Envirenment 11: 205–224. http://www.blackmeditjournal.org/pdf/2005%20vol11%20no%202-3.pdf. Retrieved 2007-05-26.