Strolling through the Shedd Aquarium with Jim Robinett is a bit like accompanying Willy Wonka on a tour of his chocolate factory.

On one stop, candy-bright fish shimmer and dart in the darkened gallery space. A moment later, he opens a hidden door. Suddenly, he’s leading the way into a chamber flooded with sunlight and filled with exotic creatures, gurgling pipes and a sign cautioning the overly curious: “STOP!!! VENOMOUS ANIMALS.”

Later, in the Oceanarium, the bulbous head of a beluga whale pops up out of the water, training its milky-gray eyes on Robinett, as if to say, “Hello.”

Or, perhaps, goodbye.

After 40 years at the Shedd, the man who’s done everything from chopping up herring and frozen shrimp to overseeing all the marine mammals in the 3-million-gallon Oceanarium, is retiring. Robinett turned 66 this week.

Jim Robinett, who is retiring after 40 years at the Shedd Aquarium, talks to his favorite animal, a beluga whale, on Thursday. | Ashlee Rezin/Sun-Times

In a concrete labyrinth somewhere beneath the Shedd’s many tanks and pools is Robinett’s cubbyhole office. Here, dripping water is a constant, though infrequent, problem, he says. Sometimes, water even leaks onto the books in the Shedd’s library.

“So the plastic comes out, cover the books real quick, find the source of the leak. The librarian angrily goes upstairs and let’s them know it’s leaking,” says Robinett, who — with rimless glasses, a balding pate and a wrinkle-free plaid shirt — brings to mind a friendly family doctor, rather than the eccentric chocolate maker.

Robinett has lots of stories about leaks. A Shedd public relations liaison fidgets slightly as he launches into the first of a half-dozen or so during a two-hour tour.

In the early 1980s, Robinett and some colleagues were on the lawn outside the aquarium after hours, watching the fireworks at Monroe Harbor. At some point, another employee came running from the building. A tank in the cold salt-water gallery had cracked.

“Water was pouring out on the floor, and a few of the smaller fish actually came out with the torrent, flopping on the floor,” he says. “We scooped them up and put them back in the holding tank. They were just fine.”

To this day, Robinett says, no one knows what caused the crack.

Jim Robinett still has one of his first ID badges from his 40 years at the Shedd Aquarium. | Ashlee Rezin/Sun-Times

Before he began working at the Shedd, water once overflowed from the giant Caribbean Reef tank overnight, pouring onto the stone floor and even spilling down the front steps, he says. It was all cleaned up, and the aquarium opened on time.

As jabbering kids gawk at the reef tank, mesmerized by a merry-go-round of exotic creatures, Robinett recalls one of his early dives in the 90,000-gallon tank as an underwater narrator. At the time, the tank had three eight-foot-long sharks. Robinett was a fresh-water guy. So sharks were a bit of a mystery. He’d heard, though, that a bump often precedes an attack.

“I’m in here with my bucket, and they start swimming in a tight circle around me,” he says. “And all of a sudden, they start bumping me in the back. … I couldn’t get the herring out of the bucket fast enough.”

The chatter of children is left behind, as Robinett opens a barely visible door that leads up a staircase to a sunny chamber — off-limits to the public — filled with concrete water tanks and cages containing everything from a porcupine to a tarantula. There’s also a colossal, floor-to-ceiling pipe with a porthole window. It’s called a “de-aeration tower,” and it releases high concentrations of atmospheric gases from the water — gases that can give fish a bug-eyed look, or worse.

“It can kill animals within a half hour. I’ve seen it happen here,” he says.

Jim Robinett, senior vice president of external and regulatory affairs at Shedd Aquarium, is retiring this week after 40 years. | Ashlee Rezin/Sun-Times

This is where the new arrivals come, those that have just been released from quarantine and are getting ready for exhibits. When Robinett grows weary of staring at his computer screen, he comes here to see what’s new. [He’s currently the senior vice president of external and regulatory affairs.]

“It’s like Christmas every morning,” he says.

The tour heads to the Oceanarium. Just beyond the curved wall of glass, flocks of Canada geese huddle on an ice-encrusted Lake Michigan. The best time of day to be here is when the sun is just peeking above the horizon, flooding the aquarium with what Robinett calls “Jesus rays.”

“Occasionally, the dolphins would come out. They’re just swimming, rubbing up against each other in a ballet,” Robinett says. “It was just so beautiful, so tranquil.”

People have often asked Robinett to name his favorite animal at the Shedd. His answer, perhaps, isn’t a surprise: The beluga.

“They look you in the eye and you feel like there is something going on, there’s some kind of communication going on,” he says. “If you do the same with a shark, all you see is a blank stare. It’s like you’re looking at the wall.”

Jim Robinett, senior vice president of external and regulatory affairs at Shedd Aquarium, says the beluga whale is his favorite aquarium resident. “They look you in the eye and you feel like there is something going on,” he says. “If you do the same with a shark, all you see is a blank stare.” | Ashlee Rezin/Sun-Times

A few years ago, Robinett was walking along the edge of one of the beluga pools, when he noticed a female, Naya, appearing to follow him. He stopped. Then she stopped too — at a gap in the acrylic wall between them.

“All of a sudden, she ducks under water, comes up with a mouthful of water and sprays it right through that gap — and nails my right leg. I was soaked,” Robinett recalls.

Naya is here on this day — her milk-white form in an upside-down glide at the bottom of the pool. She rises to the surface, tilting her head to one side, not far from Robinett.

“Hello. You’re a stinker,” Robinett says, with obvious affection. “You remember, don’t you?”

Robinett is standing at the gap, his khakis perfectly dry. Naya casts a glance in his direction, flicks her flukes before disappearing beneath the water.