The fish is an anomaly - every animal with bones requires Haemoglobin, as the protein carries oxygen around the body. It's also the protein that makes blood red.
It's a real prize for the Tokyo Sea Life Park, as it's the only aquarium in the world to have this species of fish, which was brought back to Japan in 2011 by krill fishermen.
Satoshi Tada, an education specialist at the centre, said that very little is known about the intriguing fish. The centre has a male and a female which spawned in January, and he believes that having more fish to study might help scientists discover more secrets about how the fish can live without haemoglobin.