He was the sickest turtle aquarium staff have ever come across, and now Auckland’s Kelly Tarlton's is preparing to release Calvin the Green Turtle, back into the wild, since he's better.
Rescued late last year from Northland's Ninety Mile Beach, there was little hope for his survival.
"He came to us emaciated, he had no flesh on him at all, the underside of his body was pressed in, he had a lot of lesions", said Kelly Tarlton's Aquarist, Mitchell Thornton.
Mr Thornton says he weighed just 11kgs.
"When sea turtles wash up, we can assume they haven't been eating for a long time, so they would be essentially starved, and in some cases not be strong enough to take down food at all", he said.
"At the start of it, we were taking him out of the tank at least twice a day to tube feed him."
Now Calvin's turned a corner, he’s put on at least 5kgs and his lesions are almost gone.
Kelly Tarlton's staff are proud of his progress.
Most sea turtle species, including green turtles, are endangered and Kelly Tarlton’s Aquarium cares for up to a dozen each year.
Mr Thornton says the threats to turtles are exploitation, degradation of environment, climate change and plastic.
He says he’s seen plastic pass through the systems of many turtles they’ve rehabilitated.
But, more than 40 turtles cared for at the aquarium over the years have been successfully delivered home.
Plans to return Calvin to the ocean are now in the works. His release is likely to be timed with the warmer summer waters.
Staff also told 1 NEWS while they’ve assigned him the name Calvin, they’re not exactly sure of the gender.
Mr Thornton told 1 NEWS Calvin’s about 10-years-old, and you can’t clearly identify between males and females until they reach the age of about 20.
“Their tail develops much larger, and it’s then you can tell if they’re male or female”, he said.
Before Calvin’s release back into the wild, he’s able to be seen by the public.
He’ll be swimming with the fish in the aquarium and building his muscles for a couple more months.