Acheilognathus rhombeus — a Cyprinidae from Japan, peaceful; males spar gently in breeding dress. Reaches 10.1–14.9 cm; sociable; a larger group spreads any squabbles. 15–25 °C.
Care parameters
Water temperature
15–25 °C
pH
6.5–7.5
GH hardness
5–15 dGH
Adult length
10.1–14.9 cm
Minimum tank
266 L
Water layer
Bottom-dwelling
Difficulty
Moderate
Temperament
Peaceful; males spar gently in breeding dress
Origin
Japan
Species overview
Acheilognathus rhombeus, a member of the family Cyprinidae, is native to Japan. A mussel-dependent spawner: without freshwater mussels in the system its full breeding behaviour simply never shows. It lives on the bottom. Adults reach 10.1–14.9 cm. Sociable; a larger group spreads any squabbles. Give it quiet water, a sand bed and steady maintenance; it ignores most fish foods only when they are too large. Maintain 15–25 °C at pH 6.5–7.5. A solid choice for a well-planned community tank.
Native biotope
Habitat
Clear streams and rivers over gravel
Flow
Moderate, well-oxygenated current
Dissolved O₂
Appreciates well-oxygenated water
Aquascape & hardware
Substrate
Fine gravel and sand
Hardscape
Water-worn stones and driftwood
Plants
Hardy rooted plants along the margins
Temperament, diet & tankmates
Schooling
Sociable; a larger group spreads any squabbles
Diet
Omnivore with a taste for vegetable foods and small live fare
Recommended tankmates
White-cloud mountain minnows — Share its calm, cool temperament
Avoid keeping with
Large or boisterous fish — Outcompeted at feeding time
Breeding & notes
Sexual dimorphism
Males often slimmer and more colourful
Breeding method
Spawns inside living freshwater mussels; no parental care