Gold Medaka Rice Fish

Medaka Rice Fish (Oryzias latipes)

Also known as Japanese Rice Fish

A small, hardy, and charming fish native to East Asia, particularly Japan, Korea, and parts of China and Vietnam. Known as the “Japanese rice fish” or “Medaka,” it has been a beloved aquarium species for centuries and holds cultural significance in Japan, where it is often found in rice paddies and ponds. Its ease of care, peaceful nature, and interesting behaviors (including egg-carrying before deposition) make it an excellent choice for beginners, nano tanks, or planted community aquariums. Fluorescent color variants (genetically modified with jellyfish proteins) are also popular in the trade.

Key Features

• Maximum Size: 4.0 cm / ~1.6 inches SL.
• Appearance: Slender, elongated body that is typically translucent or light-colored with subtle dark markings. Males often develop slightly longer fins and more intense coloration during breeding. The fish is known for its ability to rapidly change shade in response to its environment. Fluorescent strains display vibrant colors under certain lighting.
• Fin Details: Dorsal soft rays 6–7; anal soft rays 15–21.

Aquarium Care

• Tank Size: Minimum 10–20 gallons for a small group (nano tanks are suitable with proper maintenance).
• Water Parameters: Subtropical to tropical freshwater (also tolerates brackish); 64–75°F (18–24°C), pH 7.0–8.0, moderate hardness (9–19°dGH). Very hardy and adaptable; excellent water quality is still recommended. Provide plants, moss, or fine-leaved vegetation for cover and spawning sites. A gentle filter or sponge filter is ideal.
• Diet: Omnivorous — readily accepts high-quality micro-pellets, flakes, and small live or frozen foods (brine shrimp, daphnia, bloodworm). Feed small amounts several times a day.
• Behavior: Peaceful and active schooling fish that does well in groups. Non-aggressive and compatible with many small community fish. Females carry eggs attached to their body before depositing them on plants or substrate. Excellent for planted tanks or as a nano species. Fluorescent strains may show best color under blue or blacklight.

IUCN Status Least Concern (LC)