TACOMA -- A diver was bitten by a sand shark on Monday while he was performing regular maintenance work inside the shark tank at the Point Defiance Zoo and Aquarium.

The diver, who was a trained volunteer, is being treated at Tacoma General Hospital.

Zoo officials did not know his condition. They expect him to be released soon. He will not lose his finger.

"We're sure we followed all the safety protocols," said Dr. Karen Goodrowe, the zoo's curator. "Nothing is going to happen to the shark. It was being a shark."

This is the first time a shark has bitten anyone in the 28 years since the zoo opened the shark tank exhibit.

Divers perform maintenance inside the water every other week, replacing things like coral and other underwater objects.

While the zoo is investigating what happened, it has suspended all diving in the shark tank.