Transparent fish we knew nothing about

For the longest time, it was believed that Antarctica was lifeless at its center. What about penguins? you might ask me. Alongside other life-forms, they live near the coast.

After drilling a 3m deep hole, researchers discovered a new fish species that lived just below the ice. This fish often referred to as either “ice fish” or “white-blooded fish”, survives, thrives even, in a cold environment. Now, you might be wondering, how does say fish remain alive in such conditions? The answer is adaptation.

If you were to put a regular fish in these waters, it would freeze, but not the ice fish. After tons of research concerning their inner structure, scientists found out the secret. To not freeze, the ice fish developed a protein that acts as an anti-freeze. This protein binds specifically to little ice crystals already existent in the animal’s body. The average temperature of the water is below the freezing point, but because of the high salt concentration, it remains liquid. The anti-freeze proteins and body salts of the fish lower their freezing point just below the sea water’s, and so they can live in these waters.

Another interesting fact about this species is that it is the only known vertebrate to lack hemoglobin. Because of this trait, they also lack color and scales. Their blood is transparent. Hemoglobin is the oxygen-binding protein in the blood. Although they do not create it, remains of hemoglobin genes can be found in their genome. Oxygen is dissolved in the plasma and transported throughout the body without the protein. The ice-fish manages to survive without it due to low metabolic rates and the high concentration of oxygen in their environment.

Ice-fish have larger blood vessels, a higher blood volume, and bigger hearts to compensate for the lack of hemoglobin. Their hearts lack coronary arteries, and the ventricle muscles are very spongy, allowing them to absorb oxygen directly from the blood they pump.

It is said that there have been more astronauts into space than divers in the Antarctic Ocean. What else could we be in the dark about?!