Measure the water
GEX warns that prolonged high water temperatures can weaken medaka. Provide shade and ventilation. Temperature tolerance should not be treated as a comfortable target.
Afternoon sun: inspect the location
Thai adaptation: compare morning and hottest-afternoon readings. Use ventilated shade and check the waterline. Reconsider placement if overheating continues; avoid sudden cooling with ice or very cold water.
Rain: control overflow and runoff
Thai adaptation: divert roof and ground runoff away from the container. Provide ventilated rain protection and a regularly checked, fish-safe overflow screen. After heavy rain, inspect water level, temperature and behaviour before feeding.
Cool spells: follow conditions
Some Thai locations have cool nights and marked daily swings. Follow measured water conditions and feeding response, rather than imposing a Japanese winter schedule on your fish.
After heavy rain
- No roof or ground runoff
- Overflow screen is clear
- Water level and temperature checked
- Normal balance and breathing
References & editorial context
Sources checked on 26 September 2026. Practical recording and Thailand callouts are editorial suggestions; they are not reported Thai trial results. Source organisations have not reviewed or endorsed this article.
