The water in the fish tank is divided into two states, one is living water and the other is stagnant water. Living water refers to water that is full of vitality, rich in oxygen, flowing continuously, and has good self-purification ability and biological circulation ability. Stagnant water refers to water that lacks oxygen, contains too much organic matter, is turbid, and lacks organisms and nutrients.

The water quality in the fish tank is very important to the health and growth of fish because they need sufficient oxygen and nutrients. Therefore, only using living water can ensure the healthy growth of fish. Living water can not only maintain the balance of water quality, but also promote biological circulation in the water and improve the survival rate of fish. On the contrary, stagnant water is very detrimental to fish health. They will cause the water quality to become dirty and turbid, and lack oxygen, thus affecting the growth and reproduction of fish.

To keep the fish tank water alive, water quality management needs to be strengthened. First, change the water source regularly to keep the water quality fresh; second, add enough filter materials and microorganisms to the fish tank to create an ecological environment; finally, clean the dirt and fish feces in the fish tank regularly to maintain the transparency and freshness of the water. Only in this way can the fish grow up in a healthy environment and be lively and cheerful.