Fish talk in grunts, chirps, pops

     University of Auckland marine scientist Shahriman Ghazali says fish communicate with noises including grunts, chirps and pops. He says fish are believed to communicate with each other for different reasons, including attracting mates, scaring off predators or orienting themselves.     

     "All fish can hear, but not all can make sound - pops and other sounds made by vibrating their swim bladder, a muscle they can contract," - Shahriman Ghazali.  

     The gurnard species has a wide vocal repertoire and keeps up a constant chatter, Ghazali found after studying different species of fish placed into tanks. On the other hand, cod usually kept silent, except when they were spawning. Some reef fish, such as the damselfish, make sounds in attempts to scare off threatening fish and even divers, he said.

     "The hypothesis is that they are using sound as a synchronization so that the male and female release their eggs at the same time for fertilization," he said.

     But anyone hoping to strike up a conversation with their pet goldfish is out of luck. "Goldfish have excellent hearing, but excellent hearing doesn't associate with vocalisation - they don't make any sound whatsoever," Mr Ghazali said.

     He also says fish risk exposing themselves to predators by “talking”, so there must be a very important reason. But understanding what that reason is, or what they say, is a whole different kettle of fish.