This article is about icefishes in the family Channichthyidae. For icefishes in the family Salangidae, please see Noodlefish .

The icefishes (or white-blooded fishes) are a family (Channichthyidae) of perciform fish found in the cold waters around Antarctica and southern South America.

Antarctic icefish larvae
(click on the image for a larger version)

Their blood is transparent because they have no haemoglobin and no or only defunct erythrocytes. Their metabolism relies only on the oxygen dissolved in the liquid blood, which is believed to be absorbed directly through the skin from the water. This works, because water can dissolve the most oxygen when it is coldest. Also, their muscles (except the heart muscle) lack myoglobin. These extraordinary properties seem to be an adaption to the extreme cold of their habitat. (Note that water temperature can drop below 0 °C (the freezing point of freshwater) in the Antarctic sea, but, on the other hand, stays rather constant.)

Icefish feed on krill, copepods, and other fish.

External links

• Fishbase info for Channichthyidae (Note: They are called crocodile icefish here, but only icefish elsewhere.)
• A story about the use of the icefish for medical research