The wee reptile, weighing in at 8.1kg, had blood tests and x-rays on Monday to try to determine the mystery illness.
"Either it's just got too cold for him and he's decided to shut down, or he's got some sort of gut impaction. Or some sort of ailment.
"We're mostly just treating for cold shock and exhaustion."
The focus was on raising the green turtle's temperature to 23C and restoring fluids, said Mr Christie. it's arrival temperature was only 11C.
After three days alternating between a drip and a incubator-style box gently cascading water on to the still turtle, the patient was doing OK, said Mr Christie.
The species is resilient, he said, and could survive for weeks in a similar state of exhaustion.
The green turtle, Chelonia mydas, is listed as endangered on the red list of threatened species of the International Union for Conservation of Nature. With high body fat, the species is a key ingredient to "green turtle soup" and their eggs are still widely collected both illegally and legally.
The vet's test results are due back within the next 24 hours and will inform the next plan of action.
The turtle was joined yesterday by an Olive Ridley sea turtle and a Hawksbill turtle, which were picked up by Department of Conservation staff in Houhora and Dargaville.
Mr Christie said he had nearly a "full house" and was caring for eight turtles.
Kelly Tarlton's normally looked after six turtles a year, taking in turtles injured by boats and orcas, or those that had ingested bits of plastic or other pollution, he said.
CHOOSE A NAME
What should the turtle be named?
Yurtle.
Squirt.
Happy Flippers.
Mishelle.
Drippy.
Crush.
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