No matter what the environment, conditions, materials, etc. Not too much and not too little. If you lose your balance, something will happen. The same is true of fish farming. If there is too much oxygen in the fish tank, there will be problems. If the oxygen pump adds too much oxygen,

The dissolved oxygen in the water is too saturated, and a large amount of oxygen will form microbubbles, which will attach to the fish, and the fish will get bubble disease, which will affect the health of the fish and even die, so you can't add too much oxygen to the fish tank.