Family: Crocodile icefish
Habitat: Antarctic Ocean
This fish doesn’t just have a transparent body. It even has see-through blood! It’s the only animal in the whole world without red blood cells, meaning it doesn’t have hemoglobin (a protein that transports oxygen in the blood).
Its see-through blood isn’t good for camouflage, so what is it for? Crocodile icefish live in very, very, very cold water. It can reach 28.5 degrees Fahrenheit (-1.9 degrees Celsius).
Wait, 28.5 degrees Fahrenheit (MINUS 1.9 degrees)? How does that work, does it live in frozen water? Not quite. Water freezes at 32 degrees Fahrenheit (0 degrees Celsius). Saltwater freezes below 28.5 degrees Fahrenheit (1.9 degrees Celsius) depending on its salt content. That’s why salt is shoveled onto streets and paths in winter. These fish take oxygen from the water using their blood plasma.