KEY POINTS:
It wasn't so much a case of a fish out of water at Kelly Tarlton's but rather a close call for a washed-up yellow-bellied sea snake.
The species comes ashore only if sick, and the snake was in pretty bad shape when it was found in Northland on Wednesday. It is rare for one to be found alive in New Zealand. Three or four sea snakes sometimes wash up in a year, but they are usually dead.
Yesterday, as centre curator A.J. Christie weighed the 1.53kg adult, it had a case of the shivers and groggily moved around as it was handled. Dehydration and cold shock had taken their toll, Mr Christie said.
But when the sea snake - it is not known whether it is a male or female - took a sudden lunge upwards, the signs started to look good for rehabilitation.
"For him to start driving up, he's still got that muscle power," Mr Christie said. "It's an amazing animal. I think he's going to be all right. He looks in good nick, he's actually putting up a good fight.
"The trick's not to get bitten."
That is because as a member of the cobra family, this particular sea snake is thought to be 10 times more venomous than any land snake. Two fangs immobilise small fish, and no known antivenom exists.
Checks will still be done over the next few days for bacterial infections or gut impactions.
Warm currents are thought to have brought the traveller from Tonga, but as NZ waters are cold it washed up on Baylys Beach near Dargaville.
While sea snakes gather en masse for breeding, not much more is known about their habits.
It will call Kelly Tarlton's home until winter passes, and Mr Christie said it would get the full treatment and be fattened up before release.
SNAKE BITES
* Yellow-bellied sea snake
* Belongs to the cobra family and has venom 10 times more powerful than any land snake.
* Can dislocate its jaws and has a 180-degree range of movement.
* Feeds on small fish and shrimp.
* A handful of sea snakes wash up each year in New Zealand, but they are usually dead.