Rarely Seen Torpedo-Shaped Dragonfish Spotted Off California’s Coast

The copper-colored fish has only been seen four times in more than three decades of deep-sea research

An image of a copper-colored dragonfish. The fish resembles a long tube with short fins.
Marine biologists suspect that the dragonfish can use its tiny fins to detect vibrations and alert them of nearby predators and prey. MBARI

Scientists at the Monterey Bay Aquarium Research Institute (MBARI) spotted a rare dragonfish almost 1,000 feet below the ocean surface. Known as the highfin dragonfish, or Bathophilus flemingi, the fish is a shimmering cigar-shaped predator that can grow nearly seven inches in length. Researchers spotted the ocean-dweller while aboard MBARI's Western Flyer research vessel and took to Twitter to share their find, reports Dustin Jones for NPR.

The Western Flyer deploys and controls remotely operated vehicles (ROVs), so researchers can observe sea life at thousands of depths under the sea, reports Carly Cassella for Science Alert. Footage of the highfin dragonfish was taken at depths of nearly 1,000 feet.

Scientists have only spotted the fish four times in three decades of research and more than 27,600 hours of deep-sea footage. NPR reports that the elusive dragonfish darts around at dark depths ranging between 740 feet to 4,500 feet below the surface in the eastern Pacific Ocean off North America's western coast.

Marine biologists suspect that the dragonfish can use its tiny fins to detect vibrations and, in doing so, find nearby predators and prey, reports the Guardian's Maya Yang. When hunting, the fish floats in midwater and waits in the dark for unsuspecting fish or crustaceans. It also uses a bioluminescent filament that extends from its chin to lure prey. As prey approach, the fish readies its wide and toothy jaws for a quick bite. The team believes that the fish can also use its bioluminescence to avoid being eaten. A series of organs line the fish's flanks and allow it to match the color and intensity of the light above it, essentially erasing the fish's silhouette, reports Live Science's Cameron Duke.

While the highfin dragonfish recently spotted was a bright iridescent color, most are black, with many having the darkest pigments found in nature, NPR reports.

“They are just amazing animals, and part of what is appealing is that color pattern,” Bruce Robison, a MBARI scientist and one of the researchers who found the fish, said to Live Science. The brassy shade of the fish may be a form of camouflage that absorbs remnants of blue light, so at deep depths, the fish is nearly invisible, per Live Science. "But when we shine our white lights on it, it's just gorgeous," Robison added.