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Now what’s cooler than bein’ cool?
Icefish (Notothenioid)

 How about -1.86°C?

For those of you that may not know, this is the point at which saltwater freezes, and that my friends is pretty darn cold. These sorts of temperatures make life for a marine fish in Antarctic waters a bit chilly, especially when the thermostat dips well below the freezing point of most of their body fluids. Not to mention, ice crystals that may form in the body are pretty dangerous when it comes to puncturing important organelles  and cell walls. So what’s a fish destined to the hard, cold, watery life gonna do?

Well, a group of roughly 120 species of marine fish known as the notothenioids have resorted to just making their own antifreeze. Produced in the liver, these glycoprotein compounds are used by the notothenioids to bring the tissues in their body below the freezing point of saltwater. The proteins do this by attaching themselves to the minute ice crystals that form within the body and prevent the formation of the seed crystal needed in order for more ice crystals to be created and the whole body to freeze. Other cold water non-Antarctic fish such as Atlantic Cod, Shorthorn Sculpin, and Winter Flounder also contain this physiological mechanism, however, it is somewhat energetically expensive to produce such antifreeze compounds, so they only upregulate the production of these proteins when needed.

So Cool. Literally.

And for all of you out there who don’t know what’s cooler than being cool…OutKast is here to help.


DeVries and Cheng. 2005. Antifreeze proteins and organismal freezing avoidance in polar fishes. Fish Physiology 25, 155-201.


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