A Tidworth family had "fallen in love" with their new puppy when a check up scan revealed that she may have only six to nine months left to live.
University student Hannah Knowles, with her mum Denise Price and her partner Wayne Austen, are raising money to cover the cost of two heart operations, which they have been told will come to £10,000.
After the family lost two dogs last year, they decided to give Teddy, a lively golden cockapoo, a home in early December.
Teddy "bonded instantly" with their other dog, Ke-Ke, a four-year-old Miniature Schnauzer.
The family knew the puppy, who is now 17 weeks old, had a heart murmur, but they didn’t realise that the situation was actually more serious.
It was only three or four weeks after she joined the family that a check-up scan showed that Teddy had two heart conditions - pulmonic stenosis and PDA (patent ductus arteriosus).
Denise said: "For the first condition - PDA - they say that in six to nine months she could just have a heart attack.
"For pulmonic stenosis, they gave a life expectancy of 18 months to two years."
However, the family has been told that there is a 95 per cent chance of Teddy living a normal life after surgery.
The first operation, for PDA, will have to take place when she reaches 4 kilos in weight, which Denise says may take another two months.
They have been told that the two procedures will cost £5,000 each, though they are seeking a second opinion on having both operations done together, which should cost less.
Denise says that her pet insurance will not cover these costs.
She added: "We had fallen in love with her. It was awful, finding out the news. Looking at her, you wouldn't think there was anything was wrong with her.
"I was really shocked when the man at the hospital checked her over and said there was something wrong with her.
"She's alright at the moment but the longer it goes on, the worse it could get. It could just happen overnight."
The family have currently raised more than £2,800, and have also gathered raffle prizes from local businesses to hold a fundraising evening at The Crown pub at Ludgershall, which has yet to be arranged.
You can donate to Teddy's operations on the family's GoFundMe page.
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