An air-breathing fish which was once thought to be the missing link between fish and amphibians is on show at the Blue Planet Aquarium at Cheshire Oaks.

The bizarre bichir fish have been described as “living fossils” because they are thought to resemble the ancient amphibians which first colonised the land more than 400 million year ago.

As well as basic lungs, the fish are also capable of surviving indefinitely out of water and can even adapt their fins to walk on land.

Also known as ropefish, the freshwater species are mainly found in the Congo basin area of central Africa.

A total of seven of the fascinating fish were privately donated to the aquarium. They will spend time in quarantine before going on public display.

Blue Planet Aquarium’s Stacy Adams said: “We’ve been donated two barred bichir, a Senegal bichir and four ornate bichir.

“Ornate bichir are the largest species and can grow up to 60cm in length.

“All bichir have lungs and can survive for significant periods out of water, some species can live out of water indefinitely if they’re kept moist.

“They’re also sometimes known as “dragon fish” due to their unusual appearance. Their skin is like armour, and it has even been studied to help improve personal armour worn by police forces.”

A Canadian scientist recently carried out an experiment on a group of bichir to try and replicate the way the first amphibians changed from an entirely aquatic environment to spend more and more time on land.

She kept a number of the fish in a very shallow pool of water from a young age and compared how they developed with a group kept in much deeper water.

The results showed the fish kept out of water were able to adapt and strengthen bones which allowed them to place more weight on their fins.

Stacey added: “Bichir are definitely one of the most fascinating fish species in the world and we’re delighted to be able to add them to our collection.”