Mysterious Frisbees

Ocean sunfish can weigh over two tons , making them the heaviest bony fish in the world. Like perpendicular floating frisbees they cross the deep sea. Little is known about their behaviour. Sometimes they float lying flat on the water surface, as if they would sunbathe. Perhaps this behavior serves to warm up or for attracting birds, which relieve them from skin parasites.

On display in Hall XXVI. 

Photo © NHM Wien, Lois Lammerhuber