upside-down catfish

noun1

1. •
   Any of various freshwater catfish that swim upside-down, such as Synodontis decorus, Synodontis multipunctatus, and especially Synodontis nigriventris

   • Through the advent of air travel the amazing family of upside-down catfishes has been introduced, and is now providing us with several species of amusing and interesting scavengers. — 1963