Scientists baffled by see-through 'ice fish' with transparent BLOOD

It is unique in the animal world thanks to its astonishingly clear blood.
A Japanese aquarium has revealed its latest exhibit, a a rare 'ice fish' believed to be the only one in captivity anywhere in the world.
The fish has no scales, and its blood contains no haemoglobin, the substance that makes blood red.
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An ocellated ice fish with transparent blood, caught in the Antarctic Ocean in 2011, swims in a fish tank at Tokyo Sea Life Park

HOW DO THEY SURVIVE?

The rare ice fish can still flourish in part because of the high oxygen content of the cold waters of the Southern Ocean.
It has also developed the ability to use blood plasma to circulate oxygen through the body.
Previous studies have found these fish must expend twice as much energy in cardiac output per second than fish with higher hemoglobin concentrations.

Satoshi Tada, an education specialist at the Tokyo Sea Life Park, said very little is known about the fish, which was brought back to Japan by krill fishermen.
'Luckily, we have a male and a female, and they spawned in January,' he told AFP, adding that having more examples to study might help scientists unlock some of the fish's secrets.

 

Currently researchers are baffled by its lack of the key chemical - although researchers believe the fish can live without haemoglobin because it has an unusually large heart and uses blood plasma to circulate oxygen throughout its body.
While the majority of animal species have up to 45% of hemoglobin (or other oxygen-binding and oxygen-transporting pigments) in their blood, the ice fish has only 1%.

Researchers believe the fish can live without haemoglobin because it has an unusually large heart and uses blood plasma to circulate oxygen throughout its body

Although researchers believe the fish can live without haemoglobin because it has an unusually large heart and uses blood plasma to circulate oxygen throughout its body

They can still flourish in part because of the high oxygen content of the cold waters of the Southern Ocean and in part because oxygen is absorbed and distributed directly by the plasma, researchers believe.
Previous studies have found these fish must expend twice as much energy in cardiac output per second than the notothenioids with higher hemoglobin concentration.

The fish has no haemaglobin, which is what makes blood red and is the agent that carries oxygen around the body

Ice Fish on the sea bed