The fish blister in a fish's body is the fish organ, the swim bladder.

Fish bladders, commonly known as fish blisters, are found in hard-boned fish, most of which have swim bladders. The swim bladder occupies about 5 percent of the body's volume. Its shape is ovoid, conical, heart-shaped, horseshoe-shaped, and so on.

The gases that fill the swim bladder are mainly oxygen, nitrogen and carbon dioxide, with oxygen being the most abundant. Therefore, in an oxygen-deficient environment, the swim bladder can be used as an auxiliary respiratory organ to provide oxygen to the fish. Except for a few fish (e.g. lungfish, total finfish) whose swim bladder has a respiratory function, for most fish, the swim bladder is a body specific gravity regulating organ, which helps to regulate the body's buoyancy and sinking by means of the change of gases in the swim bladder.

Expanded Information:

The swim bladder is covered with a white, slippery mucous membrane, which is a kind of viscous material, and it is rich in nutrients. These include proteins, minerals (calcium, iron, phosphorus, etc.) and other vitamins, which are essential elements for the human body to maintain a healthy state.

In addition, the swim bladder is rich in collagen and other substances, has the effect of beauty, beauty women are more favorable to it, but also has the effect of calcium, is absolutely the best choice of tonic food.

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