Summer Heat Protection for Outdoor Medaka

Medaka are relatively heat-tolerant, but above 35°C is dangerous. Near 40°C can be lethal.

Install Bamboo Blinds or Shade Cloth The most effective measure. Place a bamboo blind over the container to block direct sunlight. Don't block light completely — create bright shade.

Use Larger Containers Greater water volume means more gradual temperature changes. Use at least 20L containers when possible. Dark containers absorb heat, so be cautious.

Top Off Water Frequently Evaporation reduces water volume and makes temperatures rise faster. Top off daily to maintain water levels.

Add Aeration Dissolved oxygen decreases at high temperatures. Solar-powered air pumps need no electrical outlet.

Add Floating Plants Floating plants like Water Hyacinth covering the surface suppress temperature rise. Thin out if they become too thick.

Reconsider Placement Move to a location away from afternoon western sun. East or north-facing balconies are ideal.