WHEN IT'S TIME for Bill Band to feed the fishies, he does more than sprinkle a pinch of dried shrimp flakes on top of the water.
Like the others who participate in the National Aquarium's volunteer diver program, Band literally submerges himself in his work.
Struggling into a wetsuit, he hoists a vest and air tank onto his back and, with a plastic container of raw, smelly fish rations in one hand, scrambles feet first down a ladder into the cool waters of the aquarium's Atlantic Coral Reef Exhibit.
What happens next is a scenario that is old hat to Band but remains one of the most popular events for millions of visitors to the Baltimore landmark. A 42-year-old Chesapeake Bay pilot and Towson resident who dives for pleasure, Band has been hand-feeding hundreds of marine animals for two days a month, almost since the aquarium opened its doors to the public a decade ago.
With crowds of children and parents watching from the spiraling ramps outside the 335,000-gallon, racetrack-shaped fish tank, Band is greeted by a hungry and mostly friendly horde of warm-water denizens.
What the fish obviously want is the four-star banquet of "cut mix" -- chopped and diced smelt, squid, shrimp, fresh clams, krill and even peas, corn and lettuce -- that the divers prepare daily in the stainless-steel aquarium "kitchen."
The food is restaurant quality, says Band, because it is most like the fresh food marine life would eat in its natural habitat. Replicating their natural diet is best for their health in the aquarium. Each day divers prepare 28 pounds of mix for the reef tank and another 10 pounds for the 270,000-gallon ray exhibit or "ray tray."
In addition to feeding the marine life, volunteer divers dispense "feed medication" to sickly fish and clean the inside of the reef tank's 28 windows.
The divers -- 54 men and 30 women -- must pass written and diving exams before they are accepted into the aquarium program. Some travel to Baltimore from as far away as Pennsylvania and Virginia for the pleasure of working inside the tanks.
For a few like Band, the volunteer program has become a family affair. Barb and Mike Axelson, Band's sister and brother-in-law, feed the fish and clean the tanks, too.
In a sense, Band is more than an interloper when he enters the artificial yet strangely exotic tank worlds. If he looks hard enough, he can see the visitors standing outside the tank. But the dry world is dimly lighted. The onlookers are silent profiles. His temporary world inside the tank is aglow with three-dimensional life. It is filled with light and sound, even if the noise is limited to the hiss and gurgle of his regulator.
"I now know what the fish feel like in your home aquarium," he says.
Angelfish, blue tang, surgeonfish, grunt, parrotfish, tarpon and bonefish gravitate toward him -- and his pungent food bucket -- in a swarm of sparkling fins and scales. Silver-colored barracuda remain aloof, waiting to snatch a few particles of flesh that drift their way when Band lets go with handfuls of chopped smelt, clams, shrimp and krill.
A couple of porcupinefish, soft-fleshed except for their bony spikes, lumber insouciantly through the excited crowd and open their jaws to receive a portion of shelled Gulf shrimp.
A brown-backed ray glides along the bottom of the tank and zeros in on some morsel dangling from Band's gloved hand. Band, a veteran of hundreds of aquarium dives, knows what spectators like.
Moving close to one of the tank's windows, he teases the ray into swimming upward for the food, exposing its soft white belly to the onlookers on the ramp. The ray opens its mouth and silently gulps its prey. Cameras flash. Through his face mask, Band can see the smiles on the other side of the glass partition. He's done his job: He's fed a hungry ray and entertained the crowd at the same time.
"You're the main attraction when you're in the tank," says Band. "The kids could care less about the fish when there's a diver in there."
Band downplays his feeding talents. "Whoever has the food bucket is the main guy to follow," he says. "You're like the Pied Piper in there."
But wait. Not everyone in this artificial sea is happy. A 160-pound Hawksbill turtle apparently wants his share of grub, too.
The turtle, whose bulk is visually magnified underwater by 25 percent, drifts like a semi-inflated dirigible into the scene. His little eyes are fixed upon a limp and lifeless squid in Band's hand. The turtle's flippers steer him to the target. He opens his beak-like mouth and bites, tearing the squid's body open and releasing a sepia-hued cloud of ink into the clear aquarium water.