Siegfried Fischbacher, half of the magician team of Siegfried & Roy — known for their glittering costumes and extravagant illusions involving tigers, lions and other animals, which made them among the most popular and highest-paid entertainers in Las Vegas — died Jan. 13 at his home in that city. He was 81.

The cause was pancreatic cancer, his publicist Dave Kirvin said.

Mr. Fischbacher and his longtime partner, Roy Horn, were inseparable throughout their career, which lasted more than 40 years. They began working together as teenagers and ended up as headliners at their own 1,500-seat theater at the Mirage hotel in Las Vegas.

Their act came to an abrupt end on Oct. 3, 2003, when a 400-pound white tiger locked its jaws on Horn’s neck and dragged him from the stage. Horn almost died of blood loss, had a stroke and never fully recovered. He died in May of covid-19, the disease caused by the coronavirus.

Mr. Fischbacher, the blond half of the German-born duo, began performing magic tricks when he was 8 and was the chief illusionist. Horn, who had a close attachment to animals from childhood, was the principal trainer of a menagerie that came to include panthers, horses and elephants, as well as the signature white tigers and white lions highlighted in every Siegfried & Roy show.

The couple, who lived at a Las Vegas compound called Little Bavaria, had met when Mr. Fischbacher was a 17-year-old steward on a cruise ship. Horn, who ran away from home at 13, was a cabin boy on the ship. In his hometown of Bremen, he had worked at the local zoo, caring for a cheetah named Chico.

At the time, Mr. Fischbacher was working on the side as a magician on the ship.

“I told Siegfried if he could make rabbits come out of a hat, why couldn’t he make cheetahs appear?” Horn recalled in a 1993 interview with People magazine. “I wanted to be part of his act, and I wanted to find a way to be with my cheetah again.”

Horn, who became Mr. Fischbacher’s stage partner in 1959, used a laundry bag to smuggle the cheetah out of the zoo onto the ship. The pair developed an illusion in which Mr. Fischbacher tore apart a stuffed toy cheetah and tossed the disjointed remnants in a box. They turned the box around, opened the lid and out jumped Chico. Over the years, Siegfried & Roy mastered more elaborate variations on the same basic trick.

“When I said to Roy, in magic, anything is possible, he believed so much,” Mr. Fischbacher told NBC’s “Today” show in 2003. “He looked at me like, ‘Oh, in magic, anything is possible?’ And he was the first one — he believed in me so much.”

Siegfried & Roy struggled for years, surviving on potatoes while feeding their animals steak. They began to gain notice in 1966, after Princess Grace of Monaco — previously known as the actress Grace Kelly — admired one of their performances. They moved on to nightclubs in Paris and Madrid before coming to Las Vegas in 1967.

“I have to tell you,” one casino owner told them, “magic don’t work in this town.”

For several years, Siegfried & Roy had a small act in Vegas-style revues, between the dancers and the showgirls. They didn’t become headliners until 1978, when their names made the marquee at the Stardust. They later moved on to the Frontier, where their show gained runaway popularity, selling out year after year.

Finally, in the late 1980s the duo signed a contract to appear at a new casino-hotel, the Mirage, being built by Steve Wynn. Siegfried & Roy were guaranteed a minimum of $57.5 million for five years, along with a $40 million theater built to their specifications. Wynn also paid $18 million to create an 88-acre animal habitat for the magicians outside Las Vegas. Variety, the entertainment publication, called it the largest contract in the history of show business up to that time.

Waiting for their new venue to be completed, Siegfried & Roy performed in Japan for almost a year, then sold out 32 shows in four weeks at New York’s Radio City Music Hall. They opened at the Mirage in 1990 with a production that Mr. Fischbacher called “not a magic show as such. It is more a spectacular with magic moments.”

A Siegfried & Roy performance encompassed the senses: There were dramatic lighting effects, music, dancers and, of course, animals. Women were magically transformed into tigers, lions appeared to levitate above the stage, an elephant vanished before the audience’s eyes. There was an implied story line hinting at death and transfiguration.

In the center of all this action and sensory mysticism were Siegfried & Roy, outfitted in shimmering, sequined costumes as they hugged and embraced the animals. People magazine called them the “Liberaces of legerdemain,” after the outrageously overdressed Las Vegas star.

Their faces were on billboards, described as “Masters of the Impossible,” and they came to symbolize the campy, over-the-top sensibility of Las Vegas as much as any entertainers before or since. Their theater was sold out for each show, two times a day (three on weekends), 46 weeks a year. They brought in $44 million a year for the Mirage.

“The show is our life, and the life is our show,” Mr. Fischbacher told “Today.”

And, for as long as Siegfried & Roy were together, for more than 30,000 performances, nothing went seriously wrong. Until it did, disastrously, on Oct. 3, 2003, Horn’s 59th birthday.

As Horn was bleeding from his neck, Mr. Fischbacher ran to his aid and heard him say, “Don’t harm the cat.” Assistant trainers emptied fire extinguishers on the white tiger until it released its grip and walked to its cage.

Many people speculated about why a tiger that had been trained by Horn since birth suddenly turned on him with near-lethal force. Animal behavior experts weighed in, and animal rights advocates were outraged. (The white tiger that mauled Horn lived until its natural death in 2014.)

The U.S. Agriculture Department, which regulates the use of large animals in entertainment, conducted a two-year investigation that reached no firm conclusions. Mr. Fischbacher suggested that Horn may have had a ­mini-stroke onstage and that the white tiger was trying to carry him to safety.

For months, Mr. Fischbacher stayed at Horn’s side during his long and incomplete recovery. He did not try to revive the act or work as a solo performer. The theater at the Mirage went dark.

“All these years,” Mr. Fischbacher told CNN talk-show host Larry King, “I always say I’m the magician and he’s the magic.”

Siegfried Fischbacher was born June 13, 1939, in Rosenheim, near Munich. His mother was a homemaker, his father a house painter who was held as a prisoner of war in the Soviet Union during World War II. He said his father became an alcoholic.

As a child, Mr. Fischbacher took up magic. He was 8, he told People magazine, “when my father came to me after I mastered my first trick and said, ‘How did you do that?’ Those few words became the opening lines of my life. It was the first time I got attention from him and the first time somebody noticed me.”

By age 20, he had formed a lasting partnership with Horn, who had a similarly troubled childhood. They never spoke publicly about the nature of their relationship, but in an autobiographical 1992 book, “Mastering the Impossible,” they said they both had relationships with women.

Horn’s mother lived with them for years in Las Vegas, and Mr. Fischbacher and Horn eventually lived in separate houses on their estate. “It is not what people think,” Mr. Fischbacher told the Los Angeles Times in 2003. “We are a perfect team.”

Survivors include a sister.

Mr. Fischbacher and Horn were active in wildlife conservation efforts and played a major role in developing international breeding programs to preserve the exceedingly rare white tigers and white lions.

After Horn’s 2003 mauling, the pair made occasional public appearances, including one modified performance in 2009 to raise money for research on brain injuries.

“Do you know what the secret to Siegfried & Roy was?” Mr. Fischbacher told the Los Angeles Times in 2003, speaking through tears. “It was the love — the audience knew it, felt it.”