cold-water fish to have black spots, which are usually caused by poor water quality. Water stimulates fish, resulting in some black spots. In view of this situation, the best solution is to gradually change the water, at least once a week, each time to change about one fifth, can also be appropriate to change more, but not more than one third.
When cold-water fish are frightened, they often have some stress reactions, such as black spots on the body surface. There are usually two reasons why it is frightened, one is the bright light, and the other is the noise. At night, avoid light affecting fish, and keep quiet to prevent noise.
If cold-water fish suffer from black spot disease, the color of the body surface will become dim, and there will be some black spots. The disease, which is mostly caused by parasites, weakens the fish, makes breathing difficult, and causes them to float on the surface of the water. If you want to treat it, you need some worming medicine.
Some cold-water fish will change color in the process of natural growth, and some places will produce black spots. This is a natural discoloration, which does not have much effect on the body of the fish. It may be that the surrounding environment is dark, so you can change the background color of the bright color to prevent blackening.
