The Kyushu bitterling (Rhodeus atremius) is a temperate freshwater fish belonging to the Acheilognathinae of the family Cyprinidae. 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 | |
|---|---|
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Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Cypriniformes |
| Family: | Cyprinidae |
| Subfamily: | Acheilognathinae |
| Genus: | Rhodeus |
| Species: | R. atremius |
| Binomial name | |
| Rhodeus atremius (D. S. Jordan & W. F. Thompson, 1914) | |
| Synonyms | |
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When spawning, the females deposit their eggs inside bivalves, where they hatch and the young remain until they can swim.
There are two currently recognised subspecies, Rhodeus atremius atremius and R. a. suigensis.[1]