Cassius, the largest saltwater crocodile in captivity, has died.

The 5.48-metre reptile, who lived on Green Island in the Great Barrier reef, was believed to between 30 and 80 years old when he was captured in the 1980s.

He was named the world record holder for largest crocodile in captivity in 2011.

Marineland Melanesia Crocodile Habitat announced the croc’s passing on Sunday afternoon, calling him “a cherished member of our family”.

“Our beloved mate Cassius … brought joy and companionship to his best mate George for over 37 years,” the social media announcement read.

George had only last month relocated to Cairns, with Cassius’s health declining soon after.

“He was very old and believed to be living beyond the years of a wild croc,” his team said online.

“Cassius will be deeply missed, but our love and memories of him will remain in our hearts forever.”

The habitat thanked everyone who visited Cassius through his life, and advised his passing may impact operating capacity in the coming days.