Mr. Bill, a 13-foot-long sawfish with a snout like a chain saw, was floating dead in his tank.
So were more than half a dozen sand tiger sharks, sleek gray creatures measuring 9 feet long. They were like so many neglected goldfish.
The macaws in the Amazon rain forest exhibit, where temperatures rose to 140 degrees in the absence of air conditioning, were clinging to life.
When a small group of workers returned to the blacked-out aquarium a few days ago, the smell was nauseating.
Once the pride of New Orleans, the Audubon Aquarium of the Americas is now a giant fish morgue.
It survived the 140-mph winds of Hurricane Katrina and the surge of floodwaters that inundated the city a day later. With a diesel-fuel generator the size of a small moving truck, they even survived the power outage -- for a while.
What creatures could possibly be better suited to survive an onslaught of water than fish?
They died by the thousands -- angelfish, sea horses, jellyfish, stingrays, piranhas.
Compared to the massive destruction and death wrought by Hurricane Katrina, this sliver of loss on the Mississippi waterfront is small.
But it echoed a lesson of the disaster: Life is fragile.
"We loved these animals," said aquarium worker Tom Dyer.
The "storm riders" were ready for the worst that Hurricane Katrina could hurl at them.
That's what the aquarium called a team of workers who volunteered to care for the 6,000 creatures in the facility, maintain the electrical and engineering systems and guard the building in an emergency.
They had everything they needed: plenty of water, boxes of military meals and inflatable mattresses. The storm riders slept in the downstairs conference room, where a window provided views of the Mississippi River.
If anything in New Orleans could survive, this was it.
The glass-and-concrete facility was built on relatively high ground just south of the French Quarter. The windows were designed to withstand 140-mph straight-line winds. The acrylic tanks, in some places, were nearly 1-foot thick, said aquarium spokeswoman Melissa Lee.
Opened in 1990, the aquarium was home to 530 species, tended to by 168 staffers. More than 18 million people had visited since its opening. Patience, an African black-footed penguin, and Mr. Bill, the sawfish, were local celebrities.
Handling the arrival of Katrina on Aug. 28 went pretty much as planned.
The storm riders switched off noncritical systems. They monitored the pumps and filters that take toxic ammonia out of the water and infuse it with oxygen. They maintained the cooling systems that kept the water for the aquarium's sea otters, Buck and Emma, chilled to a comfortable 60 degrees.
They held off on feeding the fish in order to keep the water in their tanks clear.
When the power blinked off in the early hours of Monday morning, the backup diesel generator kicked into gear just as planned.
The situation was much different outside the aquarium walls. New Orleans was beginning to disintegrate.
Thousands of evacuees had sought shelter in the Louisiana Superdome and the convention center, a few blocks to the south, expecting to stay for a night or two. Then the levees were breached. Floodwaters poured into the city, filling it like a tank.
Inside the aquarium, just a little bit of water had blown under the doors.
The storm riders munched on peanut butter and jelly sandwiches, granola and crackers as the water ravaged the city.
Mr. Bill seemed to be doing just fine.
The fish were at the mercy of the same forces that overwhelmed the rest of New Orleans.
By Tuesday, people were breaking into businesses. Some were armed, and the police were unable to stop them. Fires sparked by downed wires, broken gas lines and arsonists billowed smoke.
"They were worried about looters breaking in," said Christina Slager, a curator at the Monterey Bay Aquarium who contacted her New Orleans colleagues.
The riders had begun their vigil with 4,000 gallons of diesel fuel, enough to power the aquarium's crucial systems for four days. Now that the situation was looking like it could last much longer, they discussed ways to ration the fuel.
"The priority was rare and endangered species," said Ron Forman, chief executive of the Audubon Nature Institute, the nonprofit that operates the aquarium. The sea turtles and otter tanks would get the most power.
Audubon officials began to contemplate whether they should evacuate the storm riders or have them hang on.
With the water still rising on Wednesday morning, police warned that it could get high enough to flood the aquarium's generator.
Forman issued the order to evacuate later that day.
Before the riders left, Forman offered the aquarium to a half dozen police officers whose station had been flooded.
The police arrived, changing out of their grimy uniforms and into hats, T-shirts and shorts from the gift shop. The riders showed them how to feed the otters and the colony of 19 penguins.
The riders departed for Baton Rouge.
"We really didn't want to leave, but we didn't have much choice," said David Brandt, who cared for the penguins. "We didn't know when we'd get back in, what was going to happen."
They were gone four days.
A new team of staffers came back last Sunday afternoon, moving carefully through the aquarium with flashlights.
The generator, its air filter clogged, was barely working. The filters for the fish tanks had long stopped functioning properly, leaving the water with too much ammonia and not enough oxygen.
John Hewitt, the aquarium's director of husbandry, entered through the loading dock. It reminded him of his days as a Navy hospital corpsman in Vietnam. There was no time to think about the dead. The wounded needed tending.
"You start walking around to see what's alive," he said.
A collection of freshwater fish in the Mississippi River exhibit had died early. The police officers helped pluck them out of the tank.
The majority of the aquarium was dead by Sunday. The stench drifted out into the city.
"I've been smelling it for three days," said Sgt. Raymond Jones of the Army's 82nd Airborne Division, who has been guarding a gate near the entrance of the aquarium.
All 19 penguins survived. Buck and Emma, the sea otters, survived too, as had an anaconda, a white alligator and King Midas, a 250-pound green sea turtle.
The lacy-looking sea dragons, fragile creatures that can fail to thrive under the best of circumstances, somehow held on.
A few wild sea turtles that were being cared for at the aquarium were released into the Gulf of Mexico early in the week. The macaws and raptors were well enough to be transferred to the Houston Zoo for safekeeping.
"Each one's a little story of survival," said Chris Pierson, aquatics curator at the Newport Aquarium in Newport, Ky.
The last of the evacuees were trucked out of the Aquarium of the Americas on Friday.
The sea dragons were transported in a climate-controlled truck to the Dallas World Aquarium. King Midas, covered in wet towels, joined them for the journey, then was transferred to Moody Gardens aquarium in Galveston, Texas.
The otters and penguins were packed into large dog kennels and flown on a chartered 727 from Baton Rouge to Monterey to take up temporary residence at the aquarium there.
At a news conference Friday, aquarium officials focused on rebuilding. They stood at a podium in front of a large tank containing eight tarpon that survived along with a Kemp's Ridley turtle and an alligator gar.
But in more than a dozen tanks there was only murky, green water.
Kaplan reported from Los Angeles and Zarembo from New Orleans.