Oryzias latipes

Oryzias latipes, also called the medaka or Japanese rice fish, is a freshwater fish. It lives in small streams and waterways. Its body is grayish brown on light yellow. It has a dark brown line on its back.

These fish usually lay eggs in spring and summer. They have very strong kidneys, so they can tolerate more salt than most freshwater fish. If they get used to it slowly, they can live in seawater.

These fish live about one year and several months.

Appearance

They are approximately 3.5 centimetres (1.4 inches) long. Their dorsal and ventral fins are far in the back of their bodies.

Relationship with humans

The medaka fish spawn at about the same time of year that people put water into rice paddies, so they often live in the paddies.

Food and water

These fish eat zooplankton and the larva of mosquitoes, which live in the water.