Q. Air bladder in fish acts as ____:
Answer: Hydrostatic organ
Notes: Swim bladder is also known as air bladder for fishes. It is a buoyancy organ possessed by most bony fishes. The swim bladder is located in the body cavity and is derived from an out-pocketing of the digestive tube. It contains gas (usually oxygen) and functions as a hydrostatic, or ballast, organ, enabling the fish to maintain its depth without floating upward or sinking. It also serves as a resonating chamber to produce or receive sound.