The 3-year-old guinea pig, his hutch and bowl were stolen from the front yard of the Pettigrew family home in Glenleith overnight on Sunday.
The beloved pet was found in his home yard in Garden Pl on Tuesday with injuries including a ruptured eyeball and swollen back.
The Otago Daily Times reported yesterday the family had decided to put their injured pet down.
Two strangers contacted the ODT offering to give $1000 to pay for the surgery, but the family initially declined the offers, saying there was a "good chance" Thomas would not survive the operation.
Rachel Pettigrew said the family had a change of heart yesterday afternoon after visiting their vet and they would now be accepting donations.
Instead of being euthanised, Thomas was given some pain-killers to tide him over the weekend in the hope he would undergo surgery on Monday.
"The vets have said that although there is not a 100% guarantee he will make it through, there is a good chance that he will have a good recovery," she said.
She was also given hope by his behaviour.
"Apart from his hideous eye and back injuries he is pretty chipper. He’s still running around, he’s still eating his food."
The family was surprised and grateful at the generosity of strangers and they wanted to honour that by giving surgery a go.
Senior Sergeant Ben Butterfield said the investigation was ongoing.
A givealittle page has also been set up for Thomas.
