1. will the oxygen in the water be absorbed by the fish?

If the oxygen content in the water is not high, it will be absorbed by the fish. At this time, the symptoms of floating head will appear. For fish, the dissolved oxygen in the water will affect the health of the fish, so we must ensure that the dissolved oxygen is sufficient. Usually, oxygen pumps and other methods can be used to oxygenate, in addition, water can be changed regularly, which will also bring oxygen into the water body.

Respiratory organs: The respiratory organs of fish are their gills. All fish have gills, but some fish have auxiliary respiratory organs. For example, the African lungfish, whose swim bladder can store oxygen, continues to breathe in the wet mud after the river is dry. Douyu and Manlong have gill organs, which allow them to swim to the surface to breathe air when the dissolved oxygen in the water is insufficient. Loach can breathe through its intestines.

2. Breathing method: When the fish swims in the water, the mouth will swallow water continuously. The water will be discharged from the gills of the fish, and when it is discharged, it will pass through the gill filaments. Because the gill filaments are densely covered with blood vessels, the direction of blood flow is opposite to the direction of water discharge, so it can efficiently complete gas exchange, so as to absorb oxygen in the water.

3. Precautions: Fish usually need to breathe in water, because the gills will stick together after leaving the water, unable to exchange gases. Even some fish with auxiliary respiratory organs must breathe in a humid environment, and they will die if they are completely dry.