TAMPA— When a venomous Eastern diamondback rattlesnake appeared in the backyard of a 7-year-old girl, her German shepherd came to her rescue, refusing to back down even when the snake bit him three times.

In short, Haus is a hero.

‘‘It shows you that a rescue dog, for us, paid it forward by protecting my family,’’ said Adam DeLuca of Tampa.

Now hundreds of donors are coming to the rescue, helping to pay for the antivenom needed to keep the dog alive.

The family lives near a state park that is a habitat for rattlesnakes and cottonmouths, and dangerous critters can slip under their fence from the wilderness her father said.

The snake’s venom damaged the dog’s kidneys. Vets now expect a full recovery, but it won’t be cheap: Each day in the ICU costs between $1,000 to $1,500, and each vial of antivenom costs $618. Haus is averaging 4 or 5 vials per day as the poison leaves his system.

A family friend started the fund-raising effort. The response, said DeLuca, has been ‘‘overwhelming.’’

Haus is expected to be hospitalized for another couple of days. The family plans to forward any unused donations to a local rescue organization.

The family adopted Haus just two months ago from a rescue organization, but they already had no doubt he would risk his life to save Molly or her 4-year-old brother.

‘‘He just exceeded our expectations all the way around,’’ said DeLuca. ‘‘Right away, the kids were hugging and loving on him; he always took it, he never did anything. Whenever anyone came to the door, he would start barking and try to be protective. He has just been an amazing dog. He’s the type of dog that when you want to go buy a dog, you pay thousands of dollars and that’s the dog you get. But we adopted him and got him for free.’’