The barreleye fish is quite a rare sight that many scientists thought to have gone extinct. This is another fish that roams in the twilight zone of the ocean or the deepest part where barely any light makes it. Due to its extremely sensitive eyes, the fish has very little light to see, and this is the reason why it lurks near the bottom of the ocean.
Scientists knew they existed, some dead specimens have been caught by fishermen, but very rarely has the world seen these fish alive. The Monterey Bay Aquarium Research Institute (MBARI) in California had been observing the ocean’s shadowy twilight zone, between 600 and 800 meters (2,000 and 2,600 feet) beneath the surface, with the help of a remotely operated vehicle that has been suited with high definition cameras.
Bruce H Robison from MBARI describes how the fish uses its barreleyes to track down its prey until the very last moment:
“It always puzzled me that their eyes aimed upward, but the field of view did not include their mouths. Suddenly the lightbulb lit and I thought ‘A-ha, that’s what’s going on!’. “They can rotate their eyes.” (Quote by Bruce H Robison)
The remote deep-water vehicle even captured a stunning video of the barreleye fish moving and even rolling his eyes. The magnificence of this fish is beyond words, as described by the researchers “it is a unique sight”.
The transparent layer is like an organic shield protecting the fish's eyes and other internal parts of the head from predators. Why these fish are so rare is uncertain, as they are predatory in nature, but it is hard to find small prey or at least small enough to be preyed on by the barreleye fish as most fish at the bottom of the Ocean are of a bigger size.
Robinson has stated that in his 30 years of experience as a marine biologist he only saw 8 live specimens, including this recent one. We are talking about a person who has spent most of his life looking for these unique creatures and uncovering what hides at the bottom of the ocean.
As they are very sensitive to light and are used to the cold temperature near the bottom of the ocean, it is very difficult to bring to the surface a specimen without endangering its wellbeing. The world can only view them through videos, for now.