A fish of the genus Diodon or Tetraodon, capable of distending its body by taking air or water into its dilatable esophagus.(noun)
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Use "balloonfish" in a sentence
"Swills swelled, balloonfish bellowed, bully Billy rebelled, yellow Mell yelled, silly Will kvelled:"
"What it is: One of a family of marine or estuarine fish known as Tetraodontidae whichincludesmany familiar species variously called puffers, puffer fish, balloonfish, blowfish, bubblefish, globefish, swellfish and toadfish."