What is the ideal water temperature for koi?

The ideal water temperature for koi is typically between 65°F and 75°F (18°C to 24°C). Koi can tolerate a range of temperatures, but maintaining this range promotes optimal growth, health, and overall well-being. As temperatures drop below 50°F (10°C), koi become less active, and their metabolism slows down significantly. Conversely, temperatures above 80°F (27°C) can stress the fish and lead to oxygen depletion in the water.