The fish will float when its swim bladder expands.

The principle that fish floats can float is actually the famous Archimedes principle, which is the principle of buoyancy. That is, the buoyancy force is equal to the weight of the object displacing the same volume of liquid. The floating of the fish float is actually due to the expansion of the gas in the float, which in addition to the buoyancy generated by the elimination of liquid by its own volume, also increases the amount of liquid discharged, that is, increases the buoyancy, so the fish can swim easily in the water.

Principle

The pressure of water increases with the depth of the water. When the pressure increases, the buoyancy of the water also increases accordingly. When a fish wants to descend to the deep water layer, due to the increase in water pressure, the swim bladder contracts, the specific gravity of the fish body increases, and the fish sinks.

When it floats up, the swim bladder expands, the specific gravity of the fish body decreases, and the fish can float to the surface. Whether it is rising or falling, or staying, the process of inflating and deflating the swim bladder is carried out slowly. This is because the capacity of the variable gas is limited, so the fish cannot rise or fall rapidly in the water, otherwise there will be life. Danger.