I remember when I first started scuba diving one of the things I liked best about it was the peace and quiet; all you hear is the sound of your own bubbles. However, after several dives in the Giant Ocean Tank, I began to hear other things. To my surprise, the fish were making noise! The first sound I heard was a loud grunting noise, clearly coming from one of our Nassau groupers. It appeared to be territorial, as when he did it, a smaller Nassau grouper quickly left the area. After that experience, I began listening carefully whenever I was under water. Since then, I've heard hundreds of different noises--grunting, drumming, clicking, crackling, and squeaking. Some sounds I can identify, some I can not. Some fishes are named for the sounds they make.
For example, the black drum (left and above) makes a drumming sound, while the French grunt makes a grunting sound. Fishes make sounds for a variety of reasons. Some sounds are intentionally produced to ward off predators, discourage competitors, attract mates or as a response to fright. Involuntary sounds are usually the result of feeding or swimming. The way fishes make sounds depends on the species. Some fishes hit or rub bones together while others use muscles to contract and expand the swim bladder.
Click play to listen to the sound a black drum makes: