A heated koi pond is a specially designed pond that uses heating systems to maintain stable, optimal water temperatures for koi fish, particularly during colder seasons. By keeping the water temperature steady, usually around 50–70°F (10–21°C) depending on the koi’s needs, a heated pond helps prevent stress, promotes overall health, and supports koi activity and appetite even in winte... https://medium.com/@wwrwe4635/why-heated-koi-ponds-are-essential-for-koi-fish-health-2b3c6c21bcaa