We've been peeking through the glass at him since the year Franklin Delano Roosevelt became president.
That makes Granddad, an Australian lungfish who has lived at Chicago's John G. Shedd Aquarium for 75 years, the longest-living fish in any aquarium in the world.
"He was here when Model Ts were pulling up to the Shedd," said Roger Germann, Shedd's director of public relations. "Granddad bridges so many generation gaps."
At 4 feet long and 25 pounds, Granddad is the color of a faded brown blanket, with charcoal age spots dotting his back.
He was named by a Shedd volunteer years ago, and has gone on to become one of the aquarium's most popular residents.
"Hey! See the one with the spots -- he's been here since 1933!" a Shedd visitor shouts to a companion, while dumping half of his popcorn bag on the floor in excitement.
"I love Granddad -- he's so cool," coos a teenaged girl, pressing her nose to the tank.
Lounging at the bottom of the 6,000-gallon tank he shares with four other much-younger Australian lungfish, a few turtles and some smaller fish, Granddad is the picture of tranquility.
Playful turtles dart around him. One stops to nibble his tail.
Granddad's cloudy eyes occasionally turn to gaze out at the endless parade of humans on the other side of the glass -- just as he's been doing for three-quarters of a century.
Granddad made his journey, via steamship and train, from Sydney, Australia, to Chicago for the 1933 Chicago World's Fair.
At the time, scientists estimated that he was at least 5 years old and was fully mature.
George Parsons, director of fishes at the Shedd Aquarium, says that would make Granddad 80 now -- perhaps even 85. Scientists have no idea how long a lungfish can live, he said.
"Granddad is very comfortable," Germann said. "He gets the best care possible -- the water temperature is just right, the food is just right."
Granddad is fed three to four times a week with a variety of seafood, including smelt, small frozen fish and shrimp, Parsons said. He also likes to tear into heads of romaine lettuce that caretakers occasionally plunk into his tank.
But the old lungfish's favorite treat by far are sweet potatoes -- served raw and chopped.
"He eats really well, and looks like he is enjoying life," Parsons said.
It is not Granddad's age that makes him so sedentary, Parsons said.
Australian lungfish are not known to be active at any age. They lie in wait, camouflaging themselves and hoping to snap up anything that might be swimming nearby, Parsons said.
"They look like a big log," he chuckled.
Australian lungfish have primitive lungs in addition to their gills, and they can breathe in oxygen, Parsons said. Granddad comes to the tank's surface to get air about every 25 minutes.
The rest of the time, he usually relaxes on the tank floor.
"He's like your Uncle Fred who just likes to sit in his chair," Parsons said.
The Shedd Aquarium is planning a party for visitors to celebrate Granddad's 75th anniversary later this year. No official date has been set, Germann said, adding that the party will be for those of all ages to celebrate the life of one long-lived, well-loved fish.
"I like to think of grandparents who may come down to the Shedd today to see Granddad with their grandchildren," Germann said.
"They can look at Granddad and say, 'He was here when I was your age.'"
The world has changed enormously in the 75 years that Granddad has spent at the John G. Shedd Aquarium. Here are a few events that have taken place while he has been in his tank.
• The Great Depression took its toll during the 1930s. Movies provided escapism during that time, including 1939's "Gone with the Wind."
• In December 1941, the U.S. Naval base at Pearl Harbor was bombed, plunging the nation into World War II.
• The Cold War raged through the '50s. On a lighter note, Elvis Presley swiveled his hips and become the king of rock 'n' roll.
• The '60s saw much change and sadness with the Vietnam War and the assassinations of John F. Kennedy, Robert Kennedy and Martin Luther King. In 1969, Neil Armstrong walked on the moon.
• Watergate and the resignation of Richard Nixon rocked the nation in the 1970s. America celebrated its 200th birthday in 1976.
• Britain's Prince Charles married Lady Diana Spencer in 1981. The 1980s saw the fall of the Berlin Wall and the end of the Cold War.
• The '90s are remembered for, among other things, the first Persian Gulf War, the Monica Lewinsky scandal and the rise of the Internet. In Chicago, Michael Jordan led the Bulls to six championships.
• Americans ushered in 2000 worried about Y2K, yet only minor issues surfaced. The U.S. was shaken to its core on Sept. 11, 2001, when terrorists attacked the World Trade Center and the Pentagon.