Head to head
Blackfin Icefish vs Antarctic Toothfish
Both fish have evolved extraordinary blood chemistry to survive the freezing Southern Ocean, but in completely different ways.
| Blackfin Icefish | Antarctic Toothfish | |
|---|---|---|
| Scientific name | Chaenocephalus aceratus | Dissostichus mawsoni |
| Notable adaptation | No haemoglobin, pale colourless blood | Natural antifreeze proteins in its blood |
| Oxygen strategy | Cold water's dissolved oxygen plus skin absorption | Standard haemoglobin-based oxygen transport |
| Size | Among the largest icefish species | Among the largest fish found in Antarctic waters |
| Role in food web | Prey for larger Southern Ocean predators | Important prey for colossal squid, sperm whales, and seals |
| Conservation status | Near Threatened | Least Concern |
| Population trend | Unknown | Unknown |
| Habitat | Ocean, polar | Ocean, polar |
Blackfin Icefish vs Antarctic Toothfish: common questions
Which one lacks haemoglobin entirely?
The blackfin icefish is the one without haemoglobin, relying instead on oxygen dissolved in its plasma and absorbed through its skin, while the Antarctic toothfish retains normal haemoglobin-based blood.
Which one relies on antifreeze proteins to survive freezing water?
The Antarctic toothfish is the one with this adaptation, producing natural antifreeze glycoproteins that prevent ice crystals from forming in its blood, a trait not specifically documented in the blackfin icefish.
Which one is more important as prey for large predators?
The Antarctic toothfish plays the larger documented role, serving as important prey for colossal squid, sperm whales, and seals, though the blackfin icefish is also preyed upon by larger Southern Ocean predators.