Question

Many fish thrive in Antarctic waters where the temperature is always below zero. How do they manage to keep their body fluids from freezing?

Answer 1

they have anti freezing protein in their body. it's a kind of physiological adapatation

Answer 2

Many fishes have antifreeze compounds in their blood stream which protect them from freezing. Although there is one more factor, i.e. , water. The density of water decreases by 4° celcius and does ice floats on the surface ,the ice floating on surface acts as an insulator to the water below it. Thus helps aquatic animals to survive