Open-bellied fish are fish whose swim bladder is connected by a duct to the intestine. Removal of gases from the swim bladder during vertical movements is largely through the intestine. Open-bellied fish can swallow air, and if necessary, release it through the esophagus, pharynx, mouth. Representatives of open-bellied fish are sturgeon, herring, carp, bream, carp, carp, carp, bream, carp, pike, pike, crucian carp, roach, salmon, and eel. The open bladder has one chamber (except for carps, which have two chambers).