A team of scientists has discovered the secret that makes this bird glow.
Kryptopterus vitreolus it creates a rainbow of colors on its sides as it moves through the water. This impressive light within its glass-like body makes the native of Thailand a popular choice among aquarium owners around the world.
It also caught the attention of Qibin Zhao, an astrophysicist at Shanghai Jiao Tong University in China, as he wandered into a water store. So like any scientist who wants to know more, he decided to study.
In nature, the dancing rainbow known as iridescence is often caused by the appearance of body parts such as scales, wings, or feathers. White light hits this point and is scattered in the light, diffusing itself in ways that emphasize different wavelengths.
However, this fish allows 90 percent of light to pass through its body. It no longer has scales, and its skin is very thin (about 20 micrometers). This causes the visible spread from the skin or its scales not to be due to the rainbow; something must be at work.
With the main author Shanghai Jiao Tong University materials scientist Xiujun Fan, Zhao and his colleagues tore apart the fish to separate the skin and muscles on the back and abdomen.
The white powder passed through the skin without much dispersion. Muscles were a different story. Something in them caused the light waves to move in what is known as diffraction, creating a rainbow.
Every muscle is made up of elastic fibers called sarcomeres. Using scanning electron microscopes and optical microscopes, the team discovered that the fiber units were like gratings, splitting light into rainbows as it passed through the building.
The movement of the angles of the moving fish causes the light to hit the muscles, which makes the colors very different from the rainbow.
Some fish have the same type of tissue, but the light cannot be seen from the outside because their skin is opaque, the researchers said.
This bright glow may have occurred in ghost catfish as a camouflage technique to avoid predators, the researchers speculated.
The spirit bird is invisible; it still creates a shadow in the water that predators can hunt. This shade can be hidden by casting a stunning rainbow of colors that imitate the changing sunlight on the water.
“It is also possible that space fish can use rapidly changing species as a communication signal because we find that the fish are very human,” the researchers said.
This paper was published in Proceedings of the National Academy of Sciences.