Japanese Rice Fish (Medaka)

Oryzias latipes

Japanese Rice Fish (Medaka) (Oryzias latipes) — Easy care, Peaceful, under Other. Minimum tank in the app: 11.9 US gal min; aim for 61–75°F and pH 6.5–8.5. The Japanese Rice Fish is perfect for those who appreciate a peaceful, lively inhabitant for temperate or unheated setups.

Japanese Rice Fish (Medaka) (Oryzias latipes) in a planted freshwater aquarium
Care levelEasy
TemperamentPeaceful
Min tank size11.9 US gal min
pH range6.5–8.5
Temperature61–75°F
Max size1.6 in (4.0 cm)
Captive lifespan2–4 years
SchoolingYes · 6+ recommended

Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.

Natural distribution

Japan/Korea/China

  • East & Southeast Asia

Regional colours match the stocking calculator’s origin map.

Japanese Rice Fish (Medaka) Tank Setup

Create a visually stimulating environment with ample plants and hiding spots, particularly at the surface and mid-water where they naturally swim. Opt for a gentle water flow to mimic their natural habitat, and use a fine substrate to encourage foraging behavior. Lighting should be moderate; bright enough to support plant growth but dim enough to provide refuge for the fish.

What Do Japanese Rice Fishs Eat?

These omnivores adapt well to various foods but prefer small, slow-sinking pellets, flakes, and live or frozen foods. Their feeding behavior is generally gentle, but in mixed tanks, faster or more aggressive feeders can outcompete them, leading to decreased health and coloration.

Japanese Rice Fish (Medaka) Tank Mates

Ideal companions include other small, peaceful schooling fish that occupy different swimming zones, such as small tetras or rasboras. Avoid larger, more aggressive species that might view them as food or disrupt their schooling behavior. Inside their own species, keeping them in groups of at least six encourages natural social interactions, but avoid excessive numbers to prevent stress from overcrowding.

Are Japanese Rice Fishs Good for Beginners?

In App-aquatic we file this under easy care. That still means a cycled tank, realistic stocking, and parameters that do not swing every weekend. Aquarists often underestimate the importance of space and structure, leading to stress when fish feel exposed. Overfeeding can also be an issue, as it leads to poor water quality and health problems.

Building a community? Run the full list through the stocking calculator before you add anything else.

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