If you ever stumbled upon The Hitchhikers’s Guide to the Galaxy (not the book, but the movie) you’d surely remember not only the great opening song featuring dolphins thanking human beings for all the fish, but also the small “Babel fish,” a tiny fish from outer space able to “translate” every single language in then universe into your own. Of course, we don’t have “Babel fish” on Earth — not that we are aware of, at least — but we do have “singing fish.”
We have commonly assumed that fish are just mute (except for that Big Mouth Billy Bass on your uncle’s wall, that is). Of course, we know whales, dolphins and the like “sing” but, again, those are not fish but aquatic mammals. What we didn’t know until recently is that some fishes also know how to “sing.”
While it will be extremely difficult to listen to the inhabitants of your local aquarium singing along to a nice tune, the fact is that science has discovered that some fish species sing together, as in some sort of choir, every single day both at dawn and dusk, just as birds do, with a single tiny difference: our limited human ears cannot perceive their fishy underwater voices.
Professor Robert McCauley, of Curtin University in Australia, and his team have managed to record some of these songs: a collection of grunts, hums and foghorn-like sounds. The work took about a year and a half, and the sounds were recorded at depths ranging from 8 to 18 meters deep.