Ricefish

The Japanese Ricefish, also known as Medaka, is a small, peaceful fish from East Asia. They are one of the few aquarium fish that can be kept in outdoor ponds year-round in temperate climates, as they can survive freezing temperatures. Males develop beautiful blue-white fins during breeding season. Ricefish are hardy, adaptable, and perfect for small tanks or outdoor water features. They have been kept in Japan for centuries and are popular in nano aquariums worldwide.

Care Requirements

Tank Setup

Ricefish are perfect for small tanks or outdoor ponds.

Essential Setup:

• 10+ gallons minimum
• Plants for spawning
• Gentle filtration
• Can live in outdoor ponds
• Temperature 64-75°F (can go lower)

Water Quality

• Temperature: 64-75°F (18-24°C) - can survive freezing
• pH: 7.0-8.0
• Water Hardness: Soft to moderate (3-15 dGH)
• Ammonia/Nitrite: 0 ppm
• Nitrate: <20 ppm

Feeding

Small-mouthed omnivores:

• Micro pellets or crushed flakes
• Frozen cyclops
• Small live foods
• Will eat insects in ponds

Behavior & Compatibility

Peaceful and hardy:

• Schooling: Keep 6+ minimum
• Peaceful: Perfect nano fish
• Outdoor hardy: Can live in ponds
• Active: Constant swimmers

Good Tank Mates:

• Chili rasboras
• Ember tetras
• Small shrimp
• Other micro fish

Outdoor Ponds

Excellent pond fish:

• Survive freezing: Ice over ponds
• Natural food: Eat insects, larvae
• Breeding: Spawn in pond plants
• Year-round: In appropriate climates

Sexual Dimorphism

• Males: Blue-white fin edges when breeding
• Females: Rounder, carry eggs
• Breeding colors: Males more colorful

Breeding

Easy to breed:

• Egg layers: Eggs attach to plants
• Fry care: No parental care
• Fry food: Infusoria, micro foods
• Prolific: Produce many fry

Tips for Success

• Can live in outdoor ponds
• Survive freezing temperatures
• Perfect for nano tanks
• Hardy and adaptable
• Keep in schools
• Historical significance in Japan