Four "ugly" mutant albino turtles have gone on display after being handed in to an aquarium for safe keeping.

The Chinese soft-shelled turtles, which are classed as vulnerable by the International Union for the Conservation of Nature and Natural Resources (IUCN), were handed in to the Blue Reef Aquarium at Portsmouth, Hampshire.

The turtles, which are aged about five and will live to about 30, were given to the centre by a university student who was moving out of the city and was unable to look after them any longer.

Aquarium staff are now considering naming the foursome Leonardo, Michelangelo, Donatello and Raphael after the cartoon series Teenage Mutant Ninja Turtles.

After a period in quarantine, the four turtles, which are albino through a genetic mutation, will be added to an open-top freshwater display of giant carp.

Blue Reef's Lindsay Holloway said: "With their soft shells, extremely long neck and tube-like nostrils which they use like a snorkel they are definitely one of the world's most unusual species of turtle. Some people say they are ugly but I think they're adorable.

"The fact that these individuals are also albino makes them even more peculiar to look at. Once fully grown they can reach up to 30 centimetres in length and will provide a fascinating new addition to our giant carp display."

In Asia, the species is farmed both as a food source and as an ingredient for traditional medicine.

It has been estimated that more than 100 million turtles are sold each year, the majority being used as the main ingredient for turtle soup.

In the wild the turtle is mainly nocturnal and eats anything from crustaceans and insects to small fish and amphibians. They often lie in wait, buried in sand or mud with only their heads visible waiting to snatch at passing prey.