A fish capable of making itself invisible

©Photo taken from royalsocietypublishing.org

---

The hatchetfish , known for its blade-shaped silhouette, has the ability to make itself invisible thanks to its reflective scales capable of diffusing or diverting light, according to a study published on Wednesday.

hatchetfish (Argyropelecus) has silvery shiny scales, somewhat like aluminum, which it uses as a mirror to deceive its predators in the light of day.

"If we look at a silver fish under the blue water of the sea, we will see blue water that is reflected on the body of the fish and we also see water behind it, which makes disappear The fish, "Alison Sweeney, a researcher at the University of Pennsylvania and one of the authors of the study published in the scientific journal Royal Society Interface, told AFP.

In the depths of the ocean is another story. The scientists wondered at length how the hatchetfish could camouflage themselves in a dark environment, where their mirror scales would shine under the light beams that predators have.

This is the case of the dragonfish, which tracks its prey by means of luminous beads embedded between its eyes.

A group of scientists looked at the issue and discovered that the camouflage talent of the hatchetfish would be far more sophisticated than previously thought.

"The fish have found a way to simultaneously exercise their cunning of the mirror in ambient light and a stealth technology when it comes to predators who track him with direct light," says Alison Sweeney.

For the study, scientists have notably illuminated a mirror, aluminum and hatchetfish skin with a laser torch.

According to their results, fish scales did not reflect the laser beam directly, but spread it in several directions.

And this is not the only trick of the hatchetfish. It would also be able to redirect light from a predator to the bottom of the ocean through bioluminescent organs nestled in its stomach.

"Fish can get into big trouble if it gets hit by a light beam. So the best option to get rid of it is to reject it down, "says the researcher.

A unique combination of rectangular and elliptical scales, each reflecting light in its own way, would be at the origin of the refined camouflage of the hatchetfish.

#axfish #fish #invisible