Billabong Sanctuary are currently mourning the loss of one of their oldest crocodiles after he died of natural causes on the weekend.

Caesar, 42, passed away peacefully at the sanctuary, with staff and croc lovers left devastated by his death.

Caesar was born in 1978 at Hartley's Crocodile Adventures in Wangetti, Far North Queensland before arriving at Billabong Sanctuary in 1993.

Over the years Caesar was a star of the croc feeding shows, leaping out of the water to leave crowds in awe of his speed and power.

Head of reptiles at Billabong Sanctuary Alex Makay remembered his old mate as a gentleman.

"He was always the first crocodile people would work with because he was so calm and easy to deal with," Mr Makay said.

"We're all sad he's gone, he'll be missed a lot by us all.

"We found cancerous tumours all through his chest after he had passed away on Sunday morning. It's hard because we didn't know he was unwell, he never showed any pain."

Caesar's skull and hide will be displayed for educational purposes and contribute to crocodile conservation.

Originally published as Crocodile tears: Caesar dies, aged 42