A new fish species has been discovered in a deep area of the ocean previously thought to be devoid of fish.

Researchers uncovered the new species of snailfish a bizarre, transparent-looking creature with tiny dots in place of eyes and wide, fan-like fins an astonishing 23,000 feet (7,000 meters) below the ocean surface, in a trench in the southeastern Pacific, according to news reports from the BBC and the Australian Associated Press (AAP).

During a three-week expedition, a team of marine biologists from the University of Aberdeen's Oceanlab, along with experts from Japan and New Zealand, took thousands of images in the trench, from about 2.8 miles to almost 5 miles (4.5 km to 8 km) down.

The photos revealed startling biodiversity in the deep . The scientists saw not only the new snailfish, but also tiny crustaceans, called amphipods, which scientists have never seen living so far down.

The scientists also found a kind of deep-sea eel. The team even captured images of an eel feeding-frenzy that dragged on for a whopping 22 hours, said the University of Aberdeen's Alan Jamieson, leader of the study.

Feeding frenzy! Cusk eels, photographed 3.7 miles below the surface of the sea, swarm some tasty treats. (Image credit: University of Aberdeen.)"I'd put money on [the cusk eels] being a new species too, but that's difficult to confirm from a few photographs," Jamieson told the AAP. "We really need to bring a specimen to the surface."

Jamieson said the expedition was prompted by the group's findings in 2008 and 2009 off Japan and New Zealand, where they discovered new species of snailfish living at similar depths inside trenches.

Each trench hosted its own unique species of fish.

To determine whether the trend of unique trench species is spread across the planet, the team repeated the exploration on the other side of the Pacific Ocean, some 6,000 miles (9,656 km) distant from the previous observations.

The trench near South America did not disappoint. It boasted the widest variety of creatures the team had ever seen in a deep trench.

Next, the marine biologists are planning a return trip to the trenches near Japan, in hopes of actually capturing specimens of these strange, deep-dwelling creatures for further study.