Kyushu bitterling

The Kyushu bitterling (Rhodeus atremius) is a temperate freshwater ray-finned fish belonging to the family Acheilognathidae, the bitterlings. It originates on Kyushu Island in Japan. It was originally described as Acanthorhodeus atremius by Jordan & Thompson in 1914.^[2] The fish reaches a size of up to 6 cm (2.5 in), and is native to freshwater habitats with a pH of 6.8 to 7.8, a hardness of 20 DH, and a temperature of 10 to 25 °C (50 to 77 °F).

Kyushu bitterling
Conservation status
Near Threatened  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cypriniformes
Suborder:	Cyprinoidei
Family:	Acheilognathidae
Genus:	Rhodeus
Species:	R. atremius
Binomial name
Rhodeus atremius (D. S. Jordan & W. F. Thompson, 1914)
Synonyms
Acanthorhodeus atremius Jordan & Thompson, 1914

When spawning, the females deposit their eggs inside bivalves, where they hatch and the young remain until they can swim.

There were two currently recognised subspecies, Rhodeus atremius atremius and R. a. suigensis,^[1] but suigensis is now considered to be a separate valid species Rhodeus suigensis.^[3]