How Scientists Found Deepest-Ever Fish 5 Miles Down

— -- An underwater voyage has found an unidentified species of fish more than 5 miles down -- deeper than any other fish has ever been found before.

The white, translucent fish, found in early December in the Mariana Trench below the Pacific Ocean, was 8,145 meters, or about five miles, below the surface, breaking the previous record of 7,700 meters set in 2011 by the pink gelatinous snailfish in the Japan Trench of the Pacific Ocean by almost 500 meters, or 1,640 feet. The species has not yet been identified.

"We're pretty confident it's a snailfish," Dr. Alan Jamieson from the Oceanlab at the University of Aberdeen in Scotland told ABC News. "Not that we know. It's a new species."

The Ocean Schmidt Institute and Oceanlab carried out the 30-day voyage on the ocean vessel, the Falkor, as part of the Hadal Ecosystem Studies (HADES), an international project funded by the National Science Foundation that explores trench and hadal ecosystems. The Falkor, using unmanned landers, encountered the critter with two or three other new species of fish while recording 104 hours of footage at depths as low as 10,990 meters.

The fish is 20 centimeters in length, with a distinct snout similar to that of a cartoon dog. It also has long and very thin and fragile fins described as "tissue paper underwater," though scientists will not be able to identify it until a physical sample is captured, according to Jamieson.

"If you don't have a sample, a physical sample in your hand, you cannot do it," he told ABC News. "Which is why we can't do it for the fish."

Fish contain osmolyte, a protein that allows their cells to function under high pressures, allowing them to thrive at low depths. Scientists theorize that the lowest level at which a fish can survive at is 8,200 meters below the surface.

Timothy Shank, the director of the program and an associate scientist at the Woods Hole Oceanographic Institution, said the program hopes to capture a physical sample in the near future.

"Absolutely. No doubt," Shank said. "We put out fish traps. We put out landers that have baited traps on them. We very much want to capture these deep-sea living fish."

Other voyages in the Mariana Trench through HADES will continue, with one set in the coming weeks on the Falkor again, according to Shank. The current voyage took one physical sample of another, unidentified species of snail fish. It will take approximately one year to formally declare a name for that species.

Jamieson told ABC News that deep-sea exploration is important and necessary for learning more about fish life and the depths at which they can thrive.

"There are still things to find because we weren't expecting that," Jamieson said. "And it shows that complex animals such as fish can exist much deeper than we thought."