Schoep, the dog photographed floating with his owner in a lake which had gone viral last year, has died.

Shoep suffered from arthritis and he died just a month after turning 20-years-old.

The dog's owner, John Unger, announced the message of the German Shepherd's death with a photograph posted to Facebook. He posted a photograph of a pawprint in the sand captioned, "I breathe but I can't catch my breath."

He continued: "Schoep passed yesterday. More information in the days ahead." Tens of thousands paid tribute to the dog since the message was posted.

The viral photo of Unger and Schoep was taken by his friend after Unger feared that the then 19-year-old dog would have to be put down within a few days. The photographer, Hannah Stonehouse Hudson, took the photo at Lake Superior, where Unger helped the dog float, taking pressure off of his arthritic joints. Schoep had trouble sleeping through the night and could barely walk. The buoyancy and warmth of the water soothed the dog, and he fell asleep every time he was carried into the lake.

The photo was posted on Hudson's Facebook on Aug. 1 and was viewed by millions. Animal lovers also made online to support the dog, which allowed Unger to help pay for treatments to alleviate the dog's arthritis.

Unger told TODAY.com in September last year: "As best as I can guess, the treatments have turned back the clock on his life about a year-and-a-half to two years. I've taken him for walks on trails that we haven't been on in three years. He's not dragging his back legs like he was before. To be able to do that again with him, words can't even describe the feeling."

Since the photo went viral, a charity called Schoep Legacy Foundation has been founded, which raised over $25,000 to help low-income families take care of their aging dogs.

More photos of Shoep can be seen on Shoep and John's Facebook page.