A diver who was conducting maintenance at a zoo and aquarium in Tacoma, Washington was bitten Monday by a 4-foot sandbar shark in a tank.

The injured diver, a volunteer at the Point Defiance Zoo & Aquarium, according to the News Tribune, was taken to a Tacoma hospital for treatment of a finger injury.

It’s not clear why the shark bit the diver, but the zoo said the shark will stay in the exhibit.

The zoo has three sandbar sharks, a sand tiger shark, blacktip reef sharks, and a Japanese wobbegong, The Associated Press reported.

There's never been a shark bite at the exhibit since it opened almost three decades ago.