The water change cycle for fish farming is not fixed. According to its size and the filtration situation in the tank, some need to be changed every few days, while others can be changed every half month. Generally, the smaller the aquarium, the higher the frequency of water change. In addition, it depends on the turbidity of the water body. If the water quality is clear, it is not necessary to change the water.

Tap water is mostly used for water change. River water or well water may be polluted. After disinfection, tap water will not have other problems except residual chlorine. In order to solve the problem of a small amount of chlorine in tap water, it is generally necessary to dry it for a few days after receiving water, so that the trapped water will not harm the fish.

The amount of water to change each time does not need to be too much, generally one-fifth or one-fourth of the total amount of water. Too little change has no effect, and it is easy to stimulate the fish and produce some stress reactions. However, for some fish with solid skin, the water change can be slightly more, but usually it will not exceed one third, which is the limit of water change.

If the fish in the fish tank is sick, the water change situation should be adjusted appropriately, because there are a lot of germs in the water at this time, which need to be removed as soon as possible. At this time, the water should be changed every other day, and the amount of water should be appropriately increased, so that the stimulation to the fish will help to enhance its resistance and help it survive the disease period.