Professor Bryan Clarke, of Nottingham University, has been studying the Partula snails for the past 30 years.
They were threatened with extinction after carnivorous snails were introduced to their natural Pacific island habitat in an attempt to kill off a colony of giant African snails that had escaped into the wild from the farm where they were being bred for the restaurant trade. The plan went wrong, however, as the carnivore variety much preferred the indigenous Partula snails to the African species that they were meant to devour.
Before it was too late, Professor Clarke rescued some of the snails and took them back to the university, where they have found to thrive on a mixture of porridge, ground grass, trout pellets and chalk.
Five of the seven species that were rescued have been successfully bred and specimens have been sent from Nottingham to zoos around the world.
Professor Clarke said: "They are breeding nicely now. Their natural diet is dead leaves. Porridge is made of oats, and oats are dead leaves."
The tiny snails are fed twice a week with the porridge mix, and their numbers have now swelled to around 3,000.
Professor Clarke's assistant at the university, Vivien Frame, said: "They are really quite pretty. Some look like humbug sweets. In the last 10 years, it has been found that porridge is a good food to give to snails.
"Various mixes have been tried and it has proved to be a real success story."
Some of the Partula snails are now being re-introduced to the Pacific island of Moorea.
An electric fence connected to a car battery has been put round their enclosure to stop the carnivorous snails, called Euglandina, from getting to them.
Professor Clarke said: "Once gone, the snails will be lost forever.
"We see no hope of stopping the spread of Euglandina on the islands where it has already become established.
"But there is a very good case for discouraging new introductions.
"Our work has been successful in that it has shown that generations of snail which have been bred in the laboratory can be returned to their natural habitat."