Scientists discover ultra-black deep sea fish, among the darkest creatures ever found

The fish was found at 200 to 2,000 meters below the surface.

ByElla Torres
July 16, 2020, 5:37 PM

At least 16 types of recently discovered deep-sea fish are among the darkest creatures ever found, according to a study published Thursday.

The fish -- called the ultra-black fish, which live anywhere between 200 to 2,000 meters below surface -- are so dark that they often appear just as a silhouette, according to one of the authors, Alexander Davis, of the study, which was published in Current Biology.

"They look almost like something photoshopped out of whatever you're looking at," Davis told ABC News. "Out of the water it's a little bit different cause they're so shiny, but you can still tell they're just incredibly black."

He described them as a "matte black."

PHOTO: The Pacific blackdragon, found in the deep sea, is one of the species of black fish that absorb almost all of the light that hits their surfaces, according to a study by Smithsonian and Duke University scientists.
The Pacific blackdragon, found in the deep sea, is one of the species of black fish that absorb almost all of the light that hits their surfaces, according to a study by Smithsonian and Duke University scientists. This fish uses a bioluminescent lure to attract potential prey while its black skin and transparent, anti-reflective teeth help it stay undetected in the darkness of the ocean.
Karen Osborn/Smithsonian

To qualify as ultra-black, a species must reflect less than 0.5% of the light that hits it.

One of the fish that was recently discovered, the Oneirodes species, reflected between .044% to .051%, according to the study.

That miniscule reflection surpasses the darkness of ultra-black butterflies, which reflect .06% to .5% of light that hits them, and about equals the blackest birds of paradise, which reflect .05% to .31%, the study reported.

For comparison, black paper reflects about 10% of the incident light that hits it.

PHOTO: The ultra-black Pacific blackdragon has a bioluminescent lure that they use to attract prey, and if not for their ultra-black skin and transparent, anti-reflective teeth, the reflection of their lure would scare prey away.
The ultra-black Pacific blackdragon has a bioluminescent lure that they use to attract prey, and if not for their ultra-black skin and transparent, anti-reflective teeth, the reflection of their lure would scare prey away. The Pacific blackdragon also has light-producing organs below their eyes that scientists expect might be used as a searchlight to spot prey.
Karen Osborn/Smithsonian

Davis said the search for the fish began when his colleagues, Sonke Johnsen and Karen Osborn, wanted to photograph these particular fish. However, Davis said they kept having trouble because "they were really, really black."

"You'd either have to blast them with tons of light to see any detail or you'd just get a silhouette," he said.

They were able to capture the fish by dropping a large net down into the sea, anywhere between 200 to 2,000 meters below surface, and running it through the water.

PHOTO: One specimen of the ultra-black fish species Anoplogaster cornuta.
One specimen of the ultra-black fish species Anoplogaster cornuta.
Karen Osborn/Smithsonian

"From there, every so often something interesting pops up," Davis said.

From that point on, they worked to understand why the fish were so black.

Davis said they eventually learned their pigment was because the melanin was playing a dual role of scattering the light and absorbing it, a rarity in ultra-black creatures.

Davis believes the fish they found are just a small subset of the ultra-black fish that exist in the sea.

"It's likely there are many more of these super black deep sea fish out there," he said. "The odds that we've captured every single ultra-black fish seems really slim."