Fish have a specialized sense organ called the lateral line which works much like radar and helps them navigate in dark or murky water.  

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

October 23, 2011 | Categories: From the Gremlin

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