Koi is a species which is a Poikilothermic, which asserts that it is a cold blooded aquatic fauna. Koi are known to have a metabolism which is greatly affected by the temperature of the pond water, in which they live in.

Though being termed as a cold blooded fish species, Koi does not have the physical disposition to survive extremely cold weather. They cannot last in cold temperatures and freezing water for long periods of time, as their immunity system is known to be very delicate and weak.

In a pond with a temperature of below 10C or 50F, the Koi will find it very hard to survive, and there are probable chances of its death resulting from the lack of suitable absorption of food and metabolic activity.

Ideal Water Temperatures For Koi

The water temperature range for raising and breeding Koi, varies from 59 to around 77F, which is 15 to 25C. If the water temperature in the pool, falls below the range of 59F or 15C, the Koi will not be able to survive.

Experts assert that a water temperature of 74F is ideal for rearing Koi, and for ensuring their perfect health.

Importance Of Temperature Range

Being a species, which has a metabolic system, greatly impacted by the temperature of its surroundings; Koi is raised and bred by experienced fish owners, in a pool environment which offers the ideal pond temperature.  

This prompts the regular metabolic activity and nutritional absorption in Koi, by facilitating an environment which triggers off the appetite of the species and assists in the adequate absorption of the necessary nutrients in their body.

With an increase in appetite, the Koi will eat more and thus the toxicity level of the pond will also rise, which will need to be controlled through proper filtration. As in order to ensure the proper growth of the Koi, it is essential to provide it with a suitably chosen diet in adequate proportions, it is even more important to make sure that the pond temperature is conducive to promote appropriate consumption of food pellets as well better nutritional absorption.   

Even in winter, there are ways and means to try and raise Koi in freezing temperatures, by raising the water temperature to the required level.