Bring elegant grace and incredible hardiness to your home aquarium or outdoor patio pond with the Medaka Ricefish(Oryzias latipes). Known as the Japanese Ricefish, these delightful, active nano fish have been cultivated in Japan for centuries. Famous for their shimmering iridescence, friendly peaceful temperament, and extreme temperature tolerance, Medaka Ricefish are the ultimate addition for both beginner fishkeepers and experienced aquascapers looking for low-maintenance freshwater livestock.

Product Highlights & Care Guide

Place of Origin

Medaka Ricefish are native to East Asia, specifically Japan, Korea, and parts of China. They naturally inhabit slow-moving freshwater streams, rice paddies, marshes, and shallow ponds. Because they evolved in seasonal agricultural environments, they have developed legendary adaptability to variable weather and water parameters.

Care Level & Water Parameters

Medaka are widely considered one of the easiest freshwater fish to keep. They are extremely hardy, requiring minimal equipment compared to tropical species.

• Care Level: Beginner / Very Easy

• Temperature Range: 50°F – 80°F (10°C – 27°C) — can tolerate temporary dips down to near-freezing in deep outdoor ponds

• pH Range: 6.8 – 8.0

• Hardness: 5 – 15 dGH

Minimum Tank Size & Environment

Due to their small adult size of 1 to 1.5 inches, a small school of 6 Medaka can thrive in a 5-gallon nano aquarium, though a 10-gallon tank or larger is recommended for better stability and swimming space.

They excel in both indoor aquarium setups and outdoor mini-ponds (often kept in traditional Japanese Kingyo Hachicontainers).

• Substrate & Decor: Provide live plants such as Java Moss, Hornwort, and floating plants (Frogbit, Water Lettuce) to diffuse light and provide cover.

• Flow: Prefer calm to gentle water movement. Use a sponge filter or a baffled hang-on-back filter.

Feeding & Diet

Japanese Ricefish are micro-predators and omnivores with top-facing mouths designed to surface feed.

• Primary Diet: High-quality micro-pellets, crushed flake food, and floating nano feeds.

• Treats: Live or frozen Daphnia, baby brine shrimp, cyclops, and bloodworms.

• Pond Diet: In outdoor setups, they naturally forage on mosquito larvae, micro-crustaceans, and algae.

Compatible Tank Mates

Medaka are exceptionally peaceful schooling fish that should be kept in groups of at least 5 to 6 individuals. They will not bother other inhabitants and fit perfectly into peaceful community tanks.

• Ideal Mates: Neocaridina Cherry Shrimp, Amano Shrimp, Mystery Snails, Nerite Snails, Celestial Pearl Danios, Ember Tetras, Pygmy Corydoras, and Otocinclus.

• Avoid: Large or aggressive fish such as Cichlids, larger Gouramis, or predatory Catfish that can fit Medaka into their mouths.

Breeding Medaka Ricefish

Medaka are among the easiest freshwater fish to breed at home. Under warm water (72°F–78°F) and 13+ hours of light, females produce clusters of sticky eggs daily.

• Spawning: Females carry eggs near their anal fin before depositing them onto fine-leaved plants or specialized acrylic "egg mops."

• Rearing Fry: Transfer egg mops to a separate container with gentle aeration to prevent adult predation. Eggs hatch in 10 to 14 days, and fry can be fed liquid fry food or powdered spirulina until large enough for baby brine shrimp.

PLEASE READ BEFORE ORDERING

• The photos shown on fish product pages are representations of adult fish and are NOT the actual fish that you will be receiving. 
• Please visit our “Ordering/Shipping fish” page prior to checking out to familiarize yourself with our process.
• We ship fish exclusively using overnight shipping with either FedEx or UPS. We will not ship fish with lesser expensive shipping services like “Ground” or “Priority Mail”. This is to ensure the safety of the fish.
• Unless specified, all fish are sold as unsexed.