This fish swims upside down its entire life to catch prey.

This unusual swimming posture may help the whipfish catch larger prey faster without accidentally biting itself.

Video evidence from the deep sea shows that some species of lanternfish live their entire lives upside down, according to Pamela Hart, an associate professor at the University of Alabama who studies fish in extreme conditions. This behavior, described in the journal Fish Biology, is beyond the imagination of scientists , Phys.org reported on November 22.

The whipfish is a small fish with rod-like appendages on its face. While its body is no larger than a domestic cat, it has a spine protruding from its nose that is four times its body length. The whipfish tricks other fish using bioluminescent bacteria that live at the tip of its bait.

For nearly a century, scientists assumed that the whip-nosed lanternfish hung its lure in front of its head, much like many of its shorter-appendaged counterparts. However, new footage from underwater missions in the Atlantic, Pacific , and Indian Oceans shows the fish spending its days swimming upside down and dropping its long lure toward the seabed. The video confirms a visual observation from more than 20 years ago, according to Stewart.

In 1999, a remotely operated vehicle (ROV) spotted a whip-nosed lanternfish floating motionless with its belly facing up in the waters between Hawaii and California. Researchers suspected they were targeting prey on the seabed, but could not rule out the possibility that it was simply an unusually erratic individual.

In a video filmed near the Izu-Ogasawara Trench off the coast of Japan, a whipfish drifts along the ocean current, its body parallel to the seabed, its mouth wide open revealing hundreds of tiny teeth. Suddenly, it unexpectedly moves, using its powerful tail to swim in narrow circles. Eventually, it calms down and continues drifting, then crashes into the ROV's lighting equipment. Next, it uses its small side fins to retreat into the dark sea. In other videos, the propeller and engine of the submarine cause the pufferfish to somersault and swim belly-down, but they quickly return to an upside-down position.

According to researchers, the upward swimming posture may make the whip-nosed lanternfish more dangerous. They suspect that by keeping the bait away from its mouth, the lanternfish can take down larger and faster prey without accidentally biting itself. Stewart once encountered a whip-nosed lanternfish specimen with an enormous squid carcass in its stomach.

An Khang (According to Yahoo )

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