Danionella cerebrum, a translucent fish only 12mm in size can produce sounds exceeding 140 dB, comparable to the sound perceived by a person standing 100 m from a passenger jet during take-off.

Danionella cerebrum fish were originally identified in the 1980s, but the species was officially recognized in 2021 after scientists discovered subtle physical differences between it and Danionella translucida. The two species are so small – about the size of a human fingernail – and so similar that the differences between them could only be identified under a microscope. Recently, a team of researchers also discovered another fascinating characteristic of Danionella cerebrum, one that not only sets it apart from its genus sibling but also puts it very high up on the list of the loudest animals in the world. The tiny translucent fish uses a combination of sonic muscles and drumming cartilage to produce sounds as loud as a gunshot.

Photo: AngryBurmese/Wikimedia Commons

“This tiny fish can produce sounds of over 140 dB at a distance of 10 to 12 mm — this is comparable to the noise a human perceives of an airplane during take-off at a distance of 100 m and quite unusual for an animal of such diminutive size,” Dr. Ralf Britz, an ichthyologist at the Senckenberg Natural History Collections, said.

There are louder animals in the world, such as the pistol shrimp, which can produce sounds as loud as 250 decibels, but fishes are usually some of the quitest creatures on the planet, so it’s unusual to find one as loud as an ambulance siren or a jackhammer, especially one this small. But the mechanism Danionella cerebrum uses to produce the deafening sound is even more fascinating.

High-speed video recordings revealed that, in order to produce loud sounds, a rib located next to the fish’s swim bladder is moved by a special fatigue-resistant muscle into a piece of drumming cartilage

 

“This apparatus accelerates the drumming cartilage with a force of over 2,000g and shoots it against the swim bladder to produce a rapid, loud pulse,” Dr. Britz explained. “These pulses are strung together to produce calls with either bilaterally alternating or unilateral muscle contractions.”

Interestingly, the rib is much harder in males, which is most likely why the female Danionella cerebrum does not produce the same loud sounds. As for the purpose of the sounds, scientists have yet to discover it, but they suggest that it could help the fish navigate murky waters or it could be an aggressive tactic used by males to warn off competition during mating.