The Deep-Sea "Glutton" That Swallowed Ten Times Its Weight — Caught on Camera
A little fish in the deep has gone viral for an underdog feat: no longer than a school ruler, yet able to gulp down prey up to ten times its own mass. This time, scientists caught it on camera with its belly stretched so thin you can see its insides.
The Schmidt Ocean Institute's remotely operated vehicle SuBastian captured a black swallower fish (Chiasmodon niger) during a recent dive off the islands of Trinidad and Tobago. At 1,259 meters deep, the fish was lugging around a stomach so distended it looks like a sidecar, its skin stretched almost transparent — you can actually see its intestines and internal organs.
The fish itself is only 10 to 20 centimeters long, but the black swallower's stomach can expand like a balloon and its jaw can dislocate to open wide — an evolutionary trick for surviving in the food-scarce deep sea, where if you come across a meal, you swallow it whole, no matter how big it is.
Chief scientist Diva Amon says black swallower fish are notoriously rare to spot in the wild: "I saw my first nearly a decade ago in the Gulf of Mexico. I never imagined I'd get a second chance. But this expedition delivered BIG."
Amon wished there were a CT scanner at sea — what this little fish had for lunch may never be known. Most black swallower specimens on record were found dead at the ocean's surface, floated up by gases produced by an undigested meal inside. Sometimes the feast is fatal.
The footage comes from the Schmidt Ocean Institute's #DeepWonders expedition, exploring the waters around Trinidad and Tobago and the adjacent high seas. Ninety-three percent of the island nation's marine jurisdiction lies below recreational scuba depths — from the twilight mesophotic zone down to the pitch-black depths, among the largest deep-sea ecosystems in the Caribbean.
The geological setting is ideal for chemosynthetic habitats, cold-water coral reefs, and other ecosystems that have remained almost completely unstudied. The black swallower's appearance is just one corner of the veil being lifted. For scientists, every deep dive can bring back a new species or a new behavior — after all, humans have explored less than a quarter of the seafloor.