The fish known as Danionella cerebrum is tiny, transparent, and just 12 mm long. Its ability to make sounds louder than 140 dB has blown up scientists.
The year 2021 marked the official official recognition of Danionella cerebrum as a separate species despite its initial identification in the 1980s. It was only possible to distinguish it from its near relative Danionella translucida under a microscope due to minute physical changes. Compared to a human fingernail, these variations are significant enough to be entitled to their classification despite their tiny size. Daniella cerebrum has another fantastic trait scientists have just discovered: it can make noises that compete with those of some of the planet’s loudest animals.
“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,” explained Dr. Ralf Britz, an ichthyologist at the Senckenberg Natural History Collections.
Most fish are quite quiet; however, some animals, like the pistol shrimp, can produce noises as high as 250 dB. That’s why it’s amazing to find a fish that can produce as much noise as a jackhammer or ambulance siren—especially one that small. The Danionella cerebrum’s mechanism for producing sound adds even more intrigue.
Fast-moving video captured the fish’s unusual way of making noise. A unique fatigue-resistant muscle moves a rib adjacent to the swim bladder into a segment 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 described. “These pulses are strung together to produce calls with either bilaterally alternating or unilateral muscle contractions.”
It’s interesting to note that the male counterpart’s rib is somewhat tougher, which perhaps explains why female Danionella cerebrum do not make the same loud noises. These noises have no known function, though experts speculate that they could be males’ aggressive signal to fend off rivals during mating or a means of navigation in murky waters.
The richness and diversity of aquatic life are highlighted by the discovery of such a tremendous sound-producing mechanism in such a small fish, indicating that much remains to be discovered about the hidden potential of even the tiniest organisms.
