The gas bladder, also known as the swim bladder, is a specialized organ found in most fish that helps regulate buoyancy and maintain their position in the water column. While the term gas bladder is commonly used in biology, there are several other synonyms that refer to this organ. In some cases, it may be called an air bladder or a pneumatic duct. Other less common terms include the float, the buoy, or the swim sac. Regardless of what it's called, the gas bladder is essential for many fish species to survive and thrive in their aquatic environments.