They're not actually "talking," of course, because they don't have voices like most animals.
But they do make noises using their swim bladder, a muscle they can contract. Some of the sounds fish make are similar to grunts, chirps and pops.
"Silence is an ocean. Speech is a river." ~ Rumi
The Ocean's Depths Are Anything BUT a Vast Expanse of Silence
Jacques Cousteau, famous undersea explorer, titled his 1956 documentary on underwater life, "The Silent World."
Turns out Cousteau's diving tanks interfered with his ability to hear the virtual symphony of sounds playing beneath the water's surface.
The primary purpose of a fish's swim bladder is not for vocalization purposes, but to get him back and forth to the water's surface. When a fish wants to swim up to the surface, the bladder fills with gas. When the fish wants to descend again, the bladder empties.
Some fish are able to use this bladder to vibrate the water and produce a rather impressive array of sounds like booms, growls, thumps, whistles, and even musical notes.
These vibrations are detected by other fish. Communication among fish is thought to occur for a variety of reasons, for example for mating or spawning purposes, or to hold off predators.
Then there are fish that make sounds by grating their teeth.
Some mackerel grunts are loud enough to be heard outside the water, and the thumping sounds of drumfish submerged 60 feet under have been heard at the water's surface.
In fact, the mating calls of the black drum have been known to carry through sea walls and right into homes.
More fish sounds: