How often should you change the water in a fish tank for koi?

Koi is a popular ornamental fish and its maintenance is extremely important. Many fish enthusiasts have misunderstandings about water changes, which leads to problems with koi. Knowing the correct way to change water can not only create a clean and healthy living environment for koi, but also prevent the occurrence of diseases. Let’s find out how often we should change the water in the fish tank when we keep koi?

1. Preparation before water change

Water quality conditioner: used to purify water and remove harmful substances such as chlorine and heavy metals in water.

Thermometer: monitors whether the new water is at the same temperature as the fish tank water to avoid stress on the koi due to excessive temperature difference.

Special fish net: used to scoop out the koi so that a complete water change can be performed.

2. Change water regularly

The water quality of the Koi fish tank needs to be updated regularly, and it is recommended to do so once a week. If the water quality is poor or there is waste accumulation, the water change interval should be shortened. When changing the water, it is not advisable to change all of it at once, but to change part of it, such as changing 1/3 each time, to reduce the koi's adaptation pressure.

3. Cleaning work

Before changing the water, turn off the filter, take out the filter cotton and clean it, avoiding rubbing it with your hands to avoid damaging the filter material. At the same time, use a water pump to pump out the sewage and waste in the fish tank, and use a sponge to gently wipe the inner wall of the fish tank to remove stains.

4. Add new water

After ensuring the fish tank is clean, add new water treated with conditioner. Use a thermometer to test the temperature of the new water to make sure it is close to the temperature of the fish tank water. New water should be added slowly to avoid excessively fast water flow causing shock to the koi.

5. Adapt to the new water

After changing the water, koi need time to adapt to the new environment. If only part of the water is replaced, koi can usually adapt within 15 to 30 minutes; if all of the water is replaced, the adaptation time will be longer.

6. Monitor water quality

After changing the water, use a water quality testing tool to test the water quality of the fish tank, including pH value, ammonia nitrogen and nitrite content, to ensure that the water quality meets the survival needs of koi. If any abnormality is found, timely measures should be taken.

In general, by following these steps, you can create a suitable living environment for your koi and promote their healthy growth. Regular water changes and water testing are key to keeping your koi healthy.