The used fish tank may not be disinfected, but it is best to disinfect it to ensure the safety of the fish tank. Potassium permanganate is generally used for disinfection, which is a very common kind of medicine. After injecting proper amount of water into the tank, potassium permanganate can be added, which usually needs to be soaked for 1 hour.

If you want to raise fish, you need to raise water first. Usually, tap water is used for raising fish at home. This kind of water is not polluted, but there will be residual chlorine after disinfection. In order to remove this chlorine, it is necessary to connect the water and put it in the sun to accelerate the volatilization of chlorine through illumination, so as to make the water body safer.

Fish culture is not only fish, but also a complete ecosystem. Beneficial bacteria are needed in water, otherwise the ammonia nitrogen produced by microorganisms after decomposing fish excrement will endanger the health of fish. Usually, most of the beneficial bacteria cultured are nitrifying bacteria, which can transform ammonia nitrogen, so as to avoid fish being poisoned and improve the water environment. The method of culture bacteria is also very simple, just pour the culture liquid every week, and then turn off the lights and explode oxygen.

Wait until the water in the fish tank is turbid and clear, and you can start putting the fish. In order to ensure that the water body is suitable for fish farming, you can put a few fish in the tank to try the water first. Generally, it is necessary to choose a variety with solid skin. If there is no problem in raising it for half a month, the fish you want to raise can be put into a fish pond.