DIY Medaka Container Guide — Styrofoam & Plastic Tub Modifications

While medaka containers can be purchased, DIY builds custom environments matching your keeping style at lower cost. Outdoor keeping especially increases container quantity; buying all commercially becomes expensive. This guide covers foam box processing, plastic container drainage systems, and rain/sun protection DIY.

Using Foam Boxes as Containers

Foam boxes are excellent for medaka. They have high insulation, are lightweight, and are free or cheap to obtain.

• Obtaining Boxes: Available free to ~100 yen at supermarket fish sections or home centers. Fish shops may give large boxes
• Cleaning and Prep: Rinse fish odor with water multiple times and air-dry. Never use soap
• Size Guide: Boxes 40cm+ wide hold 5-10 medaka. Larger ensures better water stability
• Interior Color: White foam reflects light, making medaka colors fade. Line with black waterproof sheet or use black foam containers
• Reinforcement: Thin foam may bulge under water pressure. Reinforce outside with plastic crates or wooden frames
• Drainage Holes: Drill overflow holes at water level to prevent rainwater overflow. Cover holes with mesh so medaka don't escape

Foam's main advantage is insulation—it buffers summer heating and winter cooling. Cost-wise, it's superior for breeders with multiple varieties.

Plastic Container (Toro-bune) Modifications

Plastic containers (toro-bune) are most popular for outdoor medaka keeping. Stock versions work, but simple modifications greatly improve usability.

• Drainage System: Attach valve socket at lower side; install drainage valve. Water changes don't require lifting heavy containers
• Valve Installation: Use hole saw to drill plastic container bottom, fit valve socket with gasket, seal with silicone caulk
• Overflow Pipe: Mount vinyl pipe at water level to auto-drain during rain. Attach mesh to pipe end to prevent medaka escape