Koi is a common ornamental fish, its adaptability is very good, including the adaptability to water temperature. Generally speaking, it can survive in the water temperature range of 5-30 degrees. Therefore, it will not be frozen to death in winter in most parts of our country. Koi raised indoors need not worry, they will not freeze to death, because even in winter, the indoor temperature will not be too low, the water temperature is within its tolerable range.
Koi raised outdoors need to pay attention to. If there is only a thin layer of ice on the water surface, then there is generally no problem, because the water temperature in the deeper part of the pool will be higher, it will not be frozen to death. However, if the winter temperature is very low in the very north, resulting in thick ice in the pool, then the water temperature will be as low as the koi can not tolerate, it may be frozen to death.
For indoor breeding koi, water temperature can generally make it safe for winter, at this time can not need heating rod; However, if you want it to grow normally in winter, you need a heating rod. For Koi raised outdoors, it is better to transfer them indoors if conditions permit, which is safer; If there is no condition, they can only be left outdoors, then you can prepare heating rods and other tools to raise the water temperature. In the very northern part of our country, it is recommended not to put koi in outdoor fish ponds.
