The requirements of koi carp for water quality mainly include the following aspects:
Water Temperature: The suitable water temperature range for koi carp is between 20 and 25 degrees Celsius. This is the optimal water temperature range for them to show active mobility, a strong appetite, and good health.
Hardness: Koi carp prefer to live in a water environment with low hardness. Although both soft water and hard water can be used for raising koi carp, in order to avoid stress reactions in the fish, sudden changes in water hardness should be avoided. Tap water is usually soft water, while spring water and well water are hard water.
Acidity and Alkalinity (pH value): Koi carp are more suitable for living in slightly alkaline waters. The ideal pH value range is between 7.2 and 7.5. Koi carp can be raised in water with a pH value between 6 and 8.5, but they will grow better in slightly alkaline water. If the water quality is acidic, the pH value can be increased by adding sodium bicarbonate or by putting zeolite, coral sand, or oyster shells in the filter.
Harmful Substances: During the breeding process, harmful substances such as nitrite and ammonia nitrogen will gradually accumulate. Excessively high concentrations of these substances will seriously affect the health of koi carp. The content of nitrite and ammonia nitrogen should be controlled below 0.1 mg/L to prevent phenomena such as weakened mobility, faded body color, or the fish floating on the water surface of the koi carp.
The Suitable Living Environment of Koi Carp: Koi carp are suitable for living in the middle and lower layers of the water with slow water flow and relatively deep water bodies, and they forage in the sediment. They are very sensitive to changes in water quality, so special attention should be paid when introducing new fish or changing the water quality.