The most suitable water temperature range for guppies is 20 - 24 degrees Celsius. The ideal water temperatures for fry and adult fish are slightly different. The suitable water temperature for fry is 24 - 27 degrees Celsius, while adult fish prefer a water temperature of 24 - 26 degrees Celsius. Moreover, guppies can adapt to a relatively wide water temperature range and can survive between 15 - 30 degrees Celsius. However, the optimal temperature is 22 - 28 degrees Celsius. During the breeding period, the water temperature can be appropriately increased to 26 - 28 degrees Celsius to enhance the survival rate of the fry.
To keep guppies healthy, the stability of the water temperature is of great importance. Drastic fluctuations in water temperature can cause stress reactions in fish. Therefore, it is necessary to use a heating rod or cooling equipment to control the water temperature and avoid having the temperature drop below 20 degrees Celsius or rise above 30 degrees Celsius. Regularly changing part of the water and maintaining clean water quality are also crucial for keeping guppies healthy.