• Many fish communicate with sound. They make sounds by rubbing their teeth or vibrating their swim bladder. Sounds are used in courtship, male rivalry or to defend their territories. Not only do fish talk, but they also can hear! Fish can hear with an inner ear, which is also used to maintain balance. But they don't have an external ear and the sound travels through their body into the inner ear.

• In some fish, the swim bladder is near or connected to the inner ear to enhance sound reception. Fish also hear with their lateral line, a series of pressure sensitive cells along the length of their body. Fish may also use their ears to detect prey.

• For more about talking fish visit the Milwaukee County Zoo's Aquarium Exhibit.