1, fish can adjust the specific gravity of the fish body by inflating and deflating the swim bladder, which can keep the fish in the water in a stable state without sinking or floating or lifting up and down in the water.

2. The swim bladder is used to help the fish breathe. There is some oxygen inside, which can help the fish to supply oxygen in the place of oxygen deficiency. The fish borrows the swim bladder to deflate and inhale to regulate the specific gravity of the fish body, and maintain the life in different water layers

The swim bladder is located in the front of the body cavity, under the vertebrae, and the inner part is generally divided into two chambers, and there are holes on the next door of the front and back chambers, which is convenient for the circulation of the gases between two chambers, and the volume of swim bladder accounts for about 5 percent of the body, and it is one of the important organs of the body.