Why are fish covered with bubbles after changing water?

Fish are covered with bubbles after changing water, mostly because of water quality. A disease in which the nitrogen content or dissolved oxygen content in fresh water is supersaturated and enters the tissues of fish for embolism. There are many reasons for the supersaturation of nitrogen content or dissolved oxygen, such as insufficient aeration of groundwater, or too much phytoplankton and too high dissolved oxygen after sunlight exposure.

Can't use raw water. Raw water is tap water that has not been dried. The water temperature in the fish tank is too different. You can choose to change the water once a week without changing it too often. When changing water, put it in the sun for a few days to keep the water temperature similar to that of a fish tank.

Extended data:

Fish tank fish culture skills:

You can keep the fish half hungry every day, so that the digestion will be faster. Feed the fish once a day, don't feed too much at a time, and ensure that the fish are more active. Ensure that the feed is fresh, ensure that they are nutritionally balanced, and set a good time to feed. Do not change the time at will. You can choose a fixed place to feed every time.

Tap water needs to be dried for several days, and the water temperature in the fish tank is the same. It is best to use old water to raise fish, because there are more green algae in old water, which is also a very good auxiliary feed for goldfish. If it is found that the color of old green water turns to clear water and there are a lot of green algae under the tank, it is necessary to replace this water in time. This kind of water makes fish sick easily. The water changed for fish must be stored for several days, and attention should be paid to how many fish to raise.