gas bladder

plural gas bladders

1. biologyAn internal organ that fish use to control their buoyancy, allowing them to maintain or change depth by changing their density.

   1 more example

   Nicknamed a "manta" by Andromeda Initiative observers, this majestic creature has been sighted on several worlds in the Heleus Cluster. The Nexus scientists believe it may have originally evolved on a world with heavy deposits of element zero, giving it the ability to lower its mass enough to "swim" through the air. Expanding the muscular gas bladders on its underside allows the creature to rise and orient itself in flight.

   2017, BioWare, Mass Effect: Andromeda (Science Fiction), Redwood City: Electronic Arts, →OCLC, PC, scene: Andromeda Wildlife: Manta Codex entry

   Synonyms: air bladder, fish maw, swim bladder