The Betta, or Siamese Fighting Fish, is part of a group called labyrinth fishes, named because of a special organ called the labyrinth organ.  This website says, "The labyrinth organ consists of a series of folded tissues located in the head within a special cavity.  The fish gulps air at the surface of the water, holding it in the cavity where the labyrinth organ extracts the oxygen.  The fish then gulp water, flushing the labyrinth organ with water, which allows for release of carbon dioxide.  The fish then takes another gulp of air, starting the respiration cycle again."  So in other words, Bettas can breathe air.  I never knew this.  This is amazing. 

In memory of our recently deceased Betta, Warren. #nature