All bony fishes have a pneumatic duct that connects the swim bladder to the esophagus and which enables them to charge the swim bladder with air.

Question

Quizplus · Accepted Answer

Not all bony fishes have a pneumatic duct connecting the swim bladder to the esophagus. Many teleost (modern) fishes lack this connection and instead use gas exchange with the blood to regulate their swim bladder.

All Bony Fishes Have a Pneumatic Duct That Connects the Swim