The crocodile icefish or white-blooded fish (Channichthyidae) comprise a family of notothenioid fishes found in the Southern Oceanaround Antarctica. They are the only known vertebrates to lack hemoglobin in their blood as adults. Icefish populations are known to reside in the Atlantic and Indian sectors of the Southern Ocean as well as the continental shelf waters surrounding Antarctica. Water temperatures in these regions remain relatively stable, generally ranging from −1.8 to 2 °C (28.8 to 35.6 °F).One icefish, Champsocephalus esox, is distributed north of the Antarctic Polar Frontal Zone. At least sixteen species of crocodile icefish are currently recognized, although eight additional species have been proposed for the icefish genus Channichthys.