1, many bacteria. There are many bacteria in the toilet, which will affect the water quality and lead to the death of fish. Chemical disinfectants in toilets may also cause harm to fish, so they are not suitable for fish farming.
2, causing pipeline blockage. Because the bottom of the toilet and the drain pipe are not specially designed for fish farming, fish farming will produce a lot of waste and fish manure, which will easily cause the toilet to block. So it's not good to put fish in the toilet.