"Scratch," the sturgeon who loved to get his back rubbed by divers at the Pacific Beach Hotel’s Oceanarium, and hundreds of his tank buddies died yesterday when the ozone level in the 280,000-gallon aquarium got too high.

A malfunctioning ozone generator is believed to be behind the death of some 180 of the 400 or so fish that lived in the iconic three-story aquarium that forms the background of the hotel’s Oceanarium Restaurant, said Bob Beard, Oceanarium curator/manager.

"We don’t have a hard count of how many fish that we lost yet," Beard said. "We were more concerned today about avoiding more losses."

The tank water was returned to an acceptable ozone level about an hour after early morning workers discovered the dead fish, Beard said. More oxygen was pumped in, and divers removed dead fish from the tank to purify the water, he said.

Upgrading the ozone generator and replenishing the tank is next, Beard said. About 12 or 15 fish were lost about two years ago in a similar occurrence, he said.

"We’ll have a technician check the internal calibration of the ozone generator," Beard said. "We may need to make changes."

Following the generator’s malfunction, workers were thrilled that the Oceanarium’s rays lived and that the fish that they had dubbed "Sammy" and "Snaggletooth" also survived, he said.

However, several of the sturgeons that had grown unusually large during their eight years of tank life succumbed to the lethal ozone level, Beard said.

"’Scratch’ didn’t make it," he said, reminiscing about a fish who was quirky enough to stand out in a crowd.

Beard said that the fish that died were not considered rare; however, some of them had grown unusually large because of their predator-free environment or were hardly ever seen in private aquarium settings.

Since the Oceanarium’s educational outreach programs qualify it for a fish collection permit from the state Department of Land and Natural Resources, Beard said it is difficult to attach a monetary value to the loss.

"It’s more of an emotional loss," he said. "We care for and feed these fish every day. They are like puppies."

Customers like Shirley and Bob Dillon of Grayslake, Ill., who were celebrating their 60th anniversary at the Oceanarium Restaurant, also felt the loss yesterday.

"It’s really sad. We love to watch them feed the fish," said Shirley Dillon. "Each time we come to Hawaii, we eat at the Oceanarium Restaurant."

Beard’s dive team will soon begin combing Oahu for more fish to replace those lost. Built in 1979, the tank is normally host to 70 different species of Indo-Pacific marine life.