Japanese Pond Smelt (Hypomesus nipponensis)

Family: Osmeridae

Japanese Pond Smelt — a Osmeridae from Japan, peaceful open-water schooler. Reaches 7–12 cm; strong shoaler; keep in groups of 10 or more. 8–20 °C.

Care parameters

Water temperature: 8–20 °C
pH: 6.5–7.5
GH hardness: 4–12 dGH
Adult length: 7–12 cm
Minimum tank: 100 L
Water layer: Open mid-water
Difficulty: Moderate
Temperament: Peaceful open-water schooler
Origin: Japan

Species overview

A Osmeridae species native to Japan: Hypomesus nipponensis lives open mid-water over gravel. Peaceful open-water schooler. Adults reach 7–12 cm. In a community tank it pairs well with Similar-sized peaceful community fish.

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: Strong shoaler; keep in groups of 10 or more
Diet: Omnivore; prepared foods with regular vegetable matter
Recommended tankmates: Similar-sized peaceful community fish — Similar size and water needs
Avoid keeping with: Much smaller fish — May outcompete or bully tiny tankmates

Breeding & notes

Sexual dimorphism: Males often slimmer and more colourful
Breeding method: Egg-scatterer; no parental care

Frequently asked questions

Is Japanese Pond Smelt easy to keep?

Difficulty: moderate. Peaceful open-water schooler. Strong shoaler; keep in groups of 10 or more.

What temperature and water chemistry does Japanese Pond Smelt need?

Set the heater to 8–20 °C and avoid swings. pH 6.5–7.5, GH 4–12 dGH suit it.

How big does Japanese Pond Smelt get, and what tank size?

Full size is 7–12 cm. Minimum tank: 100 L, with open swimming space along its open mid-water habits.

What does Japanese Pond Smelt eat?

Omnivore; prepared foods with regular vegetable matter. Feed two small meals a day rather than one large one.

Can Japanese Pond Smelt live with other fish?

Yes, with care. Peaceful open-water schooler — pair it with Similar-sized peaceful community fish — Similar size and water needs and skip Much smaller fish — May outcompete or bully tiny tankmates.

Where does Japanese Pond Smelt come from?

Native to Japan, where it lives in clear streams and rivers over gravel. Moderate, well-oxygenated current; Appreciates well-oxygenated water.

Does Japanese Pond Smelt jump?

Not a noted jumper — a standard cover still keeps dust and spray in.

How does Japanese Pond Smelt breed?

Egg-scatterer; no parental care. Males often slimmer and more colourful.