Ocellated Ice Fish
The only captive specimens of the Ocellated Ice Fish are housed in the Tokyo Sea Life Park. Aside from its rarity in captivity, this clear-blooded fish has the distinction of not having hemoglobin. All vertebrates, with the exception of Channichthyids, are supposed to have hemoglobin in order to transport oxygen in blood. The Ocellated Ice Fish can be found in the deep, freezing waters of the Antarctic Ocean. These fish have evolved to cope with the cold and along the way disposed of the need for red blood cells.
For more information on this fish, visit PHYS.ORG. If you would like to read more about Channichthyids and their unique evolution, visit Biochemical Soul.