An overweight Rottweiler from Devon that was at risk of being put down has shed 40kg after a regime of swimming.
The diet and exercise also changed the dog's behaviour
Six-year-old Shamrock weighed 99.8kg when his owners decided he had to diet.
After eating proper food and swimming 10,000 metres over eight months in the family pool in Plymouth, he now weighs a comfortable 60kg.
His owner Mandy Moore said: "We had to come up with some idea to make him lose weight and get fit, he would have had to be destroyed or he would have died."
She said the pedigree dog was twice the weight he should have been.
Shamrock weighed twice as much as a normal Rottweiler his age
"So we came up with the idea of swimming.
"Now his temperament is a lot better. He runs, he plays, he's inquisitive. He is always willing to go out and never refuses anything. He is a completely different dog."