The water in the fish tank is clear, so it is not necessary to change the water. Usually, there is no fixed period for changing water, but it must be before the water quality deteriorates. If the water body is turbid, it may be too late to change water again. If it is a small fish tank, it should be changed once every three or four days because it contains less water. If the fish tank is larger, it can be changed once a week. If the fish tank is large and the filtration system is powerful, it is not unreasonable to change it once every two weeks.

1. Trapping water in advance: To change water for fish tank, you must first trap water in advance. Because tap water is the most commonly used for fish farming, tap water contains a small amount of chlorine, which is harmless to human body, but may affect fish, so it is necessary to dissipate chlorine in water by trapping water. There are many ways to trap water, which can be put in the sun to dry or aerated.

2. Pumping water: After fresh water is prepared, you can start changing water. To change water, the old water in the tank should be pumped out before fresh water can be injected. Don't pump too hard when pumping old water, otherwise the fish will be frightened. The same is true when injecting water. Be sure to slowly inject new water into the cylinder from the cylinder wall.

3, pay attention to the water temperature: Pay attention to control the water temperature when changing water. If the temperature suddenly increases or decreases, it will stimulate the fish as well. Therefore, it is necessary to measure the water temperature of the fish tank first, and then mix new water according to this water temperature, and add cold water or hot water to it until the temperatures of the two are close to the same.