Coldwater · Beginner care

Japanese ricefish

Oryzias latipes

Japanese ricefish is rated beginner here because of its adult size, water range and social needs. Use plants or wood for cover while leaving room for the school to move.

Japanese ricefish (Oryzias latipes) in an aquarium
Photo: Seotaro · CC BY-SA 3.0
Adult size4 cm (1.6 in)
Minimum tank10 US gal
Temperature59–82°F (15–28°C)
pH range6.5–8.5
Group size6+ fish
Swimming levelMiddle to upper

Is Japanese ricefish a good aquarium fish?

Japanese ricefish reaches about 4 cm as an adult, so plan around the adult fish rather than the juvenile size seen in shops. The suggested minimum of 10 US gallons assumes suitable filtration, open swimming space and routine maintenance.

Generally peaceful in a suitable community. Keep the recommended group of at least 6 fish and avoid mixing it with tank mates that need a very different temperature, water chemistry or swimming level.

Water and aquarium setup

A stable temperature of 15–28°C and pH of 6.5–8.5 are the working ranges in the planner. Stability and clean, oxygenated water matter more than chasing a single target number.

Use plants, wood or rock to create cover while leaving the open swimming space this species needs.

Diet

Quality small pellets or flakes, supplemented with frozen foods and occasional vegetables.

Compatibility notes

Japanese ricefish is generally workable in a community aquarium when the tank mates share its temperature range and social needs.

Use the Stocking & Bioload Planner to check a proposed community. Its estimated bioload value for one adult japanese ricefish is 0.46 units; this is a planning heuristic, not a replacement for testing nitrate.

Common mistakes

  • Planning around the shop size instead of the adult size.
  • Adding a schooling fish in a group smaller than its social minimum.
  • Ignoring the tank's length, floor area or lid because the gallon number looks adequate.
  • Adding fish before the aquarium is cycled and ammonia and nitrite are consistently zero.

Care ranges are conservative summaries of commonly cited husbandry references. Individual fish, strains and local water can differ; monitor the aquarium and adjust the plan gradually.

Photo source: Seotaro · CC BY-SA 3.0. The local copy is resized for page performance.