No fish can be raised in closed wells. The water in the well is groundwater, which has a relatively low temperature and can't guarantee the water depth. When it reaches a certain depth, there will be huge water pressure, and ordinary fish can't stand it. Moreover, the hardness of well water is relatively high, because it is infiltrated by surface water, and various ions will be adsorbed in the process, so this water quality is not suitable for the survival of fish, and it is not very good for fish farming.

1. Drying: If well water wants to raise fish, the first thing to do is to dry it. After the water is packed, put it in a sunny place, and raise the water temperature by sunlight. At the same time, some impurities in the water can be precipitated. After such treatment, its hardness can be reduced, which is more suitable for the survival of fish.

2. Oxygen injection: Because the well water itself has little contact with air, the oxygen content is very low. In addition, in order to reduce the hardness of the water body, it needs to be heated, which will further lose oxygen. Therefore, it is necessary to increase its dissolved oxygen by oxygen injection, otherwise it will not raise live fish.

3. Filtration: In fact, there are many ways to reduce the hardness. Besides drying and heating, it can also be filtered, or soft water resin can be used to adsorb ions in water, which can also reduce the hardness and control its ph to make it become weakly acidic or weakly alkaline water.