Photos of a giant sunfish washing up on a south Australian beach are going viral, after being snapped by a longtime fisherman.

The 1.8-metre-long specimen had a massive dorsal fin, rough skin and didn鈥檛 appear to be a creature at all.

Linette Grzelak told CTVNews.ca over Facebook that her partner, professional fisher Steven Jones, initially 鈥渢hought it was a piece of driftwood.鈥

Jones and his colleague spotted the sunfish as they were driving along the beach at Australia鈥檚 Coorong National Park on Saturday.

Although Jones had heard of these creatures before, Grzelak said 鈥渋t was his first time seeing one in real life.鈥

鈥淏ut he knew what it was when he got closer,鈥 she said, adding Jones soon realized the creature was also dead. 鈥淏ecause they were at work, they left it there and it got taken back out with the tide.鈥

Ocean sunfish are one of the heaviest bony fish species on Earth and are regularly found in temperate marine waters, according to the . They typically have a large head, long dorsal fin and a disproportionately small mouth.

But Grzelak admits she鈥檇 never before seen or heard of a sunfish, who are also called Mola mola. 鈥淲hen he sent me the photo, I didn鈥檛 even think it was real. It looked fake,鈥 she said.

Grzelak explained that most people likely would have missed the fish, as the beach which Jones works on is only accessible by boat and is mainly used by the those in the fisheries industry.

On Tuesday, National Parks South Australia re-posted the photos on Facebook with the caption describing the 鈥渦nusual surprise for two fishers on the weekend.鈥

The park鈥檚 post also explained, 鈥渢hese huge beauties 鈥 can weigh more than a car.鈥 Because of the sunfish鈥檚 dorsal fin, the creature is sometimes mistaken for a shark, when it swims close to the shore.

Although Grzelak鈥檚 photos have circulating in several different places, the photo set on National Parks South Australia been shared 296 times on Facebook, with more than 700 people reacting to them online.

Grzelak said, 鈥淚 never expected all this attention for a fish. It has been crazy.鈥