Backstage at the New England Aquarium

At 8 a.m., an hour before the New England Aquarium opens, Skip Schneider and his coworkers are armed with spray bottles, attacking the mundane but important job of polishing the glass to create crystal-clear views for visitors of the aquarium's collection.

Mr. Schneider is our host for today's behind-the-scenes tour. He works in the Fishes Department as a senior aquarist. Like all his colleagues in the aquarium's West Wing, a much-needed addition that opened in January, he owns a college science degree, as well as a deep devotion to and knowledge of the aquarium's resident population.

"This is a 24-hours-a-day job," says Schneider, who was a volunteer before getting a fulltime position. "We have beepers and the night watchman has our home phone numbers. If the water temperature in one of the tanks drops or a tank overflows, we might get a call at 2 a.m."

Built over Boston Harbor at Central Wharf, the aquarium is moderate sized by today's standards.

Only a block away from the city's bustling Faneuil Hall Marketplace, it is a tourist attraction that brings 1.1 million visitors through the turnstiles each year, including flocks of schoolchildren.

Fish and sea mammals are not all that inhabit the aquarium. On this morning the staff of 18 in the Fishes Department are tending to some of the seabirds and reptiles in the "Coastal Rhythms" exhibit.

One of Schneider's tasks is to serve meatballs on the rocks, literally, to a group of saltwater crocodiles, called "salties" by the staff.

Before entering the exhibit with its life-like mangrove trees, he assures his visitors that he's in no danger. These are shy, timid baby crocs about a foot long, not the adults that can weigh a ton or more. Not long after he sets out their dinner, the crocodiles come onto shore and begin to gobble meatball after meatball.

The food, including the tiny brine shrimp fed to eery garden eels that protrude from the sand, is prepared in an industrial-looking kitchen, where a large freezer is stocked with crates of restaurant-quality fish and squid, as well as dried food. Upstairs is the "live food" room, where worms and bugs are cultivated and stored.

Caring for the aquarium collection also means cleaning the inside of exhibits (some artificial plants are even removed, cleaned, or replaced every several days).

While Atlantic puffins frolic in the water, Heather Brown scrubs the rocks both above and below the water's surface. It looks far more strenuous than washing the kitchen floor.

In a neighboring exhibit, Steve Baker, whose specialty is seabirds, meticulously grooms a manmade beach, raking out the droppings and reshaping the simulated natural contours, made of 20,000 pounds of sand. Five fresh pallets of sand are delivered each month.

An animal in a manmade habitat is generally more sensitive to subtle differences than one in the wild. For this reason, conditions in the aquarium must be closely monitored and habitats properly broken in.

"You can't just throw in the fish the night before an exhibit opens," Schneider says. Every fish that comes in is quarantined and observed for 30 days.

Clean water and proper water temperatures are a priority. Workers do not use chemically treated tap water except for washing their hands.

Tropical fish like the water to be 78 to 80 degrees F, while giant Japanese spider crabs prefer it in the chilling 45-to-55 degrees range.

A clipboard hangs near every tank for logging conditions and making relevant notes (if, for example, an animal is being bullied by other fish or eating poorly, the situation will be reported to the aquarium's veterinarian).

Staffers work in passageways that run behind the exhibits and are a half floor higher than the public concourses. This elevation provides workers with the right angle to peer down into the tank and tend its occupants.

One favorite is a Pacific octopus with a span of about six feet. Schneider says she is "incredibly friendly and very inquisitive," reaching out to run her suction cup-covered tentacles over the arms of the aquarists at feeding time. Schneider compares her grip to a firm handshake.

Another prized possession is an exotic leafy sea dragon, which reaches 8 to 10 inches when fully grown and is found only one place in the world - off the south coast of Australia.

Extra caution is exercised in transporting such a rare species. This one flew in the passenger section of a commercial plane, packaged and accompanied by a specialist at the Dallas Aquarium, which is loaning the sea dragon to the New England Aquarium.

Such cooperation is not uncommon among aquariums, and several look to Boston's to supply them with jellyfish.

The aquarium's biggest body of water is a 187,000-gallon coral reef tank, where sharks and Myrtle the Turtle swim amid numerous smaller species. The lumbering turtle is the only animal with a name. "We're extremely dedicated to the animals, but we don't want to get too personal," Schneider explains.