Unassuming dragonfish lurk in the twilight zone, more than 1,600 feet under the surface of the ocean. Dark, eel-like, and roughly three and a half inches long, these deep-sea creatures glow with bioluminescence and have evolved a complex sensory system that allows them to detect even the subtlest movements in the ocean’s shadowy realms, then attract and capture their prey.

In a paper published Wednesday in the journal Matter, scientists demonstrated another layer of complexity to the dragonfish: the thin, jagged teeth of the species Aristostomias scintillans are made of nanoscale-size crystal particles. The composition and structure of these nanocrystals make the dragonfish’s fangs transparent and stronger than the teeth of some of the fiercest fish predators, such as great white sharks and piranhas.

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The new findings have intrigued both marine biologists and material scientists. Dragonfish aren’t strong swimmers, so researchers have wondered how they eat.

“They’re basically hanging out in the water column,” said Jacqueline Webb, a fish biologist at the University of Rhode Island. “Because they cannot be studied alive in the laboratory, any observation that can lend insights into the biology of these fishes is really valuable.”