One of the world’s smallest transparent fish roars as loud as a gunshot

Fish employs unique strategy

This fish is of immense scientific value due to its transparency, which enables researchers to closely observe various biological functions, including brains in action. 

“Due to its small size and lifelong optical transparency, the fish Danionella cerebrum is an emerging model organism in biomedical research,” the study mentioned. 

However, how this 12mm long marine species produced such high sounds has remained a mystery. 

Using high-speed video recordings, the team delved into the fish’s mechanism of sound production. They also combined micro-computed tomography (micro-CT), RNA profiling, and simulations to better understand the underlying process. 

Unlike most fishes that use their swim bladder to create sounds, this transparent fish species employs a different strategy. 

The team discovered that the Danionella cerebrum possesses a distinctive sound production system. It produces a strong rhythmic sound by drumming on an organ known as a swim bladder.

As per the research paper, this system involves a “drumming cartilage, specialized rib, and a fatigue-resistant muscle.” 

Together, these components enable the fish to achieve remarkable acceleration of the drumming cartilage with extreme forces. As a result, the fish can generate rapid and loud pulses, producing sounds that reach over 140 decibels. 

This unique apparatus sets the Danionella cerebrum apart from other fishes and showcases an extraordinary adaptation for sound production in this tiny aquatic creature.

Interestingly, the team found the rib is much harder in males, which explains why females do not produce these remarkable sounds.

High sound may be for communication

While scientists have yet to determine the exact explanation for the fish’s loud sounds, it is hypothesized that they may represent a sort of social communication.

Reportedly, the sound may aid in navigating muddy waters or be used by males as an aggressive approach to deter competition.

“Understanding this extraordinary adaptation expands our knowledge of animal motion and highlights the remarkable diversity of propulsion mechanisms across species, contributing to our broader understanding of evolutionary biology and biomechanics,” the study authors mention in the research paper. 

As per BBC, scientists have been aware that certain creatures, like pistol shrimp, are capable of generating extremely loud noises. Its sound can reach as high as 200 decibels, especially during their hunting activities. 

Additionally, other fish species, such as the Plainfin Midshipman and the Black Drum, emit extremely high-pitched sounds. However, all of these species exceed Danionella in size. 

Researchers propose that danionella might be the most vociferous fish species of its size.

The findings were reported in the journal Proceedings of the National Academy of Sciences.