The aquarium of ornamental fish has mixed water quality, yellow color and white bubbles. How to solve it?

There are white spots on the cylinder wall, which should be that your water temperature is high, and the weather is hot recently, so you didn't pay attention to cooling down. The residue of food leads to the proliferation of bacteria, and after washing the vat, these things are flooded. Although you changed the water, there was no comprehensive treatment, so it recurred. I suggest you use filtration method first, filter cotton with activated carbon, and completely filter out the water [if it is too serious, you can consider using a water purifier urgently]. Then, use malachite green or potassium permanganate to disinfect the utensils in the tank, and add potassium blue or methyl blue to the water in the tank. In fact, malachite green is ok, but it is not good for small fish, so it is best not to use it. This should be cured, but we should pay attention to maintenance in the future, and the water temperature should not be too high.