New Orleans Ten aquarium visitors, including four children, fell into a shark tank and thrashed around in terror for up to 15 minutes with the animals swimming beneath their kicking feet before they were pulled out.
No one was seriously hurt, though one of the children, a 2-year-old girl, later woke up screaming in the night.
The visitors fell in Wednesday night when a catwalk over the water collapsed.
One of the onlookers, 8-year-old Amanda Kruse, said most of the sharks scattered, but she saw one cruising underneath the panicked guests.
"Its lips were peeled back and its teeth were showing," Amanda said.
Officials at the Aquarium of the Americas were investigating what caused the accident at the Gulf of Mexico exhibit, which includes about 24 nurse sharks and sand tiger sharks, some of them 10 feet long. The aquarium Web site warns visitors: "You'll be glad you're on the outside looking in."
The catwalk is normally reserved for staff but was opened for a behind-the-scenes tour for aquarium members. When it buckled, the group was thrown into the 20-foot-deep, 400,000-gallon tank along with a 38-foot section of the platform.
"All of sudden I heard something go bam, and the long catwalk split in half right in the middle and it dropped everybody straight into the water," said Dan Rooney, whose two daughters, 2-year-old granddaughter and 5-year-old nephew plunged in.
Daughter Allison Rooney, 21, told CNN: "Ironically, the man was telling us that if anybody ever fell into the water, that the sharks are well-fed and that they would scatter. ... Well, not even two seconds later, sure enough the whole thing just collapsed."
The water level is about 3 feet below the slick edges of the glass-walled tank, so there was no way for those inside to pull themselves out without help. Many clung to the mock oil platform in the center of the tank. Adults tried to hold small children above the water, splashing around and scattering sandals, makeup kits and brochures inside the tank.
"The water is clear so you could see the sting rays and sharks swimming beneath them," Dan Rooney said. "I know the sharks are well-fed, but with all that splashing you wonder if their hunter instincts are going to kick in."
Like many of those who fell in, Erin Rooney, 14, was scraped by the barnacle-encrusted support poles of the mock oil platform.
"It happened so fast I didn't really think about the sharks at first, I just wanted to get out of the water," said Erin, who is Allison's sister. "I never wanted to go near the sharks, and the worst part is I was scared to go on the catwalk and people were making fun of me for not wanting to go on it."
Allison Rooney was able to hand 2-year-old daughter Amber to a rescuer after they fell in. But she had to swim to the other side of the tank to get out her rescue took 15 minutes.
"It was very scary," she told CNN. "When I first looked down, I saw a sting ray right underneath me and I just freaked out. I was scared to death what I would do if I saw a shark."
The aquarium was opened for business Thursday, but the shark tank was curtained off.