The silver spinyfin, or little dori, inhabits a layer of the deep sea, where the Twilight Zone’s blue fades to black, often half a mile below the surface. Down there, they may see the world like no other animal known to science.

Scientists have generally understood that color vision wasn’t necessary in the deep sea. It’s too far for sunbeams to penetrate, and so there’s no light to give way to color. But in a study published Thursday in Science, researchers interested in the evolution of color vision analyzed the genomes of 101 different fishes. They discovered that one, the silver spinyfin, has more genes for discriminating dull light than any other vertebrate on the planet. These genes make it possible to see the whole range of residual daylight and the full spectrum of bioluminescence in the deep sea. Other fishes may have this ability to detect color in the deep sea, too.

“In vertebrate fishes, nothing has been seen like this before,” said Megan Porter, who studies how vision evolved at the University of Hawaii at Mānoa and was not involved in the research. “This goes against what we understood as how visual systems evolved in the deep sea, which means we have to question how visual systems work and function in the dim light.”