a liquid, typically one based on ethylene glycol, which can be added to water to lower the freezing point, chiefly used in the radiator of a motor vehicle.This is the definition of antifreeze.
Antifreeze is a form of alcohol and is used in car ratdiators to prevent the water from freezing.
(Alcohol -just so you know- freezes at -202 degrees.
Water at 32 degrees and sea water at 28.5 degrees.)
Now you're probably wondering how a fish can be anti-freezable.
Well God created a bunch of fish that live in the Antarctica near the Ross Sea *(see the Ross Ice Shelf). They live in extra cold water.
One fish is called Dragonfish.
All these fish have a special protein in their blood that is a form of antifreeze that keeps their blood from freezing in such frigged water.
It's just another amazing thing that God did.