It is very simple to change water in an ordinary small fish tank. First find a pipe to pump out the water, and then slowly add new water. Usually, the water used for fish farming is tap water, which is not polluted, but after disinfection, there will be residual chlorine, so it needs to be trapped for several days, and it can only be used after chlorine volatilizes clean. When pumping water, one end of the pipe should lead to the bottom of the tank, and the other end should be placed at a place lower than the fish tank. You can pump out the water by taking a sip.

1. Water change cycle: First of all, we should pay attention to the water change cycle when changing water. Because of the different sizes of fish tanks and the different fish raised, the cycle of changing water is often not fixed. If it is fast, it will be changed once every three days, and if it is slow, it can be changed once every half month. How often to change water depends on the maintenance of water quality.

2. Control the amount of water: The amount of water changed usually does not exceed one third of the total amount, and the more frequent the water change, the less water will be changed each time. If the water is changed once every three days, only about one fifth of it needs to be changed every time, and if it is changed only once every half month, it should be changed once more appropriately, so as to improve the water quality.

3. Keep the water temperature: During the water change period, the most important thing is to keep the water body. If the temperature changes greatly, the health of fish will also be affected to some extent. Therefore, before changing water, it is best to measure the water temperature in the fish tank first, and then allocate new water according to this temperature to ensure that the temperatures of the two are consistent.