Scientists have discovered one of the world’s smallest fish is capable of making sounds registering more than 140 decibels – which is louder than a pneumatic drill.
The translucent Danionella cerebrum is just 12mm-long and has the smallest known brain of any vertebrae.
The sound was first noticed by scientists studying the species in Berlin, Germany, who could hear sounds as they walked past the fish tanks.
Researchers then set up high-speed cameras on a tank containing the fish to work out exactly what was going on.
“The fish are so loud that, even when just walking past their tanks, you can hear audible pulsing sounds,” Verity Cook, the study’s lead author, told New Scientist.
The sound is produced when one of the fish’s ribs is pulled into its swim bladder, creating a “drumming sound”.
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It is only the males who make the noise and the reason they do is unclear – but Ms Cook thinks it might be to help them communicate and locate each other in murky waters.
“The fact that it’s only males that make sound suggests that it’s to do with aggressive behaviour towards other males or mating behaviour with females,” she said.
The study has been published in the journal, Proceedings of the National Academy of Sciences.
