Fin's Fish Guide
The Japanese rice fish (Oryzias latipes) is a fish that lives in both fresh and salt water of the family Adrianichthyidae that grows up to 4 cm.
East Asia (Japan and surroundings), in rice fields, ditches, ponds and slow-flowing water; tolerates brackish water.
Description
The Japanese rice fish or medaka is a small, hardy surface fish of the family Adrianichthyidae (ricefishes) reaching about 4 cm. The body has a flat back, an upturned mouth and large eyes, suited to life just below the water surface. The species comes from Japan and its surroundings and lives in rice paddies, ditches, ponds and slow-flowing water; it tolerates brackish water and large temperature swings. As an omnivore it eats zooplankton, insect larvae (including mosquitoes) and algae. Notably, the female carries the fertilised egg cluster as a bunch on her belly for a time before the eggs attach to plants. The medaka is a major research animal in genetics and developmental biology worldwide and popular in the aquarium hobby.
Frequently asked questions
How do you recognise the Japanese rice fish?
The Japanese rice fish has an elongate, eel-like body, is mainly yellow-gold and shows a plain pattern. Small, hardy surface fish with a flat back, an upturned mouth and large eyes; the female carries the egg cluster around with her for a time like a bunch.
Where does the Japanese rice fish live?
The Japanese rice fish lives in both fresh and salt water and is mostly found around algae or seagrass beds. East Asia (Japan and surroundings), in rice fields, ditches, ponds and slow-flowing water; tolerates brackish water.
How big does the Japanese rice fish get?
The Japanese rice fish grows to a maximum of about 4 cm.
Is the Japanese rice fish dangerous to humans?
No, the Japanese rice fish is harmless to humans. None required: this species is harmless to humans.
Is the Japanese rice fish edible?
The Japanese rice fish is not usually eaten.
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All data
Identification
Appearance
Habitat & distribution
Behaviour & biology
For anglers
Safety
Status & sources
Same genus Oryzias
More from the family Adrianichthyidae
Want the complete picture on the Japanese rice fish?
Point your camera at the fish and Fin names the species in seconds. Free, and the Japanese rice fish is one of 12,519 species in the app.