The world’s record holder for deepest fish goes to the brotulid* family, about which scientists know almost nothing. These fish are benthopelagic, living at depths of 7000 meters or more. The world’s deepest fish (Abyssobrotula galatheae) was found in the Puerto Rican Trench at a depth of 8,372 meters (that’s over five miles down!). Unfortunately, the fish didn’t survive the trip to the surface.

Their eyes appear to be virtually nonexistent. Maybe it’s because there is never enough light for the fish to see, so why bother with the eyes? After all, eyes in most organisms are designed for gathering light in the creature’s visual field and transmitting it to the brain – giving it useful information about its environment. In a world where no sunlight ever penetrates there’s probably little use for eyes. The brotulids probably have other, highly developed senses to compensate for their lack of vision, which help them to find their way around in the dark depths. Maybe YOU could be the scientist who studies this species and unravels its mysteries.