Some fish make sounds by grating their teeth and others, like some catfish, make sounds from their air-filled swim bladder.

Some fish, like sharks, don’t posses an air bladder to help keep them afloat and must either swim continually or rest on the bottom.

March 29, 2013 | Categories: From the Gremlin

 

Some fish, like sharks, don’t posses an air bladder to help keep them afloat and must either swim continually or rest on the bottom.