After buying a palatial home outside Los Angeles, Elise Ingram and her husband debated what to do with a "very 70s" built-in circular seating area in the living room. They considered turning it into a wine cellar.

Instead, they opted to fill it with sharks.

The couple installed a 500-gallon aquarium, where they put a leopard shark and a houndshark, both about two feet long, three sting rays and a few yellow tangs.

It didn’t go swimmingly. The houndshark immediately began "frantically trying to get out of the tank," Ms. Ingram said. She called the aquarium company to remove it. "He was messing with the vibe of the tank."

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One of the other fish in the tank fared even worse. It was chomped during a shark feeding frenzy and left "twitching in the corner."

For some reason, sharks have become a new must-have accessory for luxury homes.

Real-estate developers and high-end buyers—including celebrities like Lil’ Wayne and Tracy Morgan—are installing elaborate aquariums so they can keep the ocean’s most feared predators as pets.

A shark tank owned by Tracy Morgan. Acrylic Tank Manufacturing

They are also finding that keeping predators with multiple rows of knife-sharp teeth is often, well, complicated. Sharks are expensive to maintain and surprisingly finicky about water conditions.

The tank alone can cost from $15,000 up to $1 million, said Brett Raymer, co-founder of Acrylic Tank Manufacturing, based in Las Vegas. The company builds about 20 shark tanks a year in private homes, some of which hold up to 16,000 gallons of water.

It is legal to own sharks, which can cost anywhere from a few hundred to thousands of dollars, according to Mr. Raymer. Some species, like great whites, are protected, and cannot be kept in homes.

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Owning a shark can be "a power thing," said Joe Caparatta, owner of Manhattan Aquariums and Unique Corals, who has owned catsharks and epaulette sharks in the past. "The shark is the most feared animal in the waters. To have one as a pet kind of puts you above it."

Mr. Caparatta said he gets frequent requests for large sharks such as blacktips, but tries to steer his customers toward smaller species that are easier to take care of. "These big sharks don’t do well in captivity," he said, while smaller species "are much better suited to life in a glass box."

Ario Fakheri, a physician and real-estate developer, built a home with a shark tank in the Hollywood Hills and is putting a 15,000-gallon shark pond in the backyard of his own Los Angeles home. He called sharks "one of the sexiest animals out there."

This $35 million home built by developer Ario Fakheri in the Hollywood Hills comes equipped with around eight sharks. Neue Focus Photography

Mr. Fakheri said he has loved sharks since he was a child, when he loved watching the movie "Jaws." While that film’s murderous great white doesn’t seem like an ideal pet, he said the danger adds to sharks’ allure.

"Now you control them," he said. "It’s payback."

After Ms. Ingram sent the houndshark back, she turned the air conditioner off before leaving the house during a heat wave. When she came back, the leopard shark was dead. "Apparently sharks don’t like hot water," she said. "I didn’t know they were that sensitive to temperature."

She bought two more leopard sharks, which also soon died. When she replaces them, she said she plans to install a better temperature control system for the tank.

Stories like this one are exactly why shark ownership should be undertaken with great caution, experts say.

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"In general, I would say don’t get a shark as a pet," said Joe Yaiullo, curator and co-founder of Long Island Aquarium. But for those determined to own a shark, he recommended the smaller, bottom-dwelling species, like bamboo sharks or catsharks, and researching them in advance to make sure the tank is large enough to accommodate them throughout their lives.

With a nurse shark, for example, "you can buy it at 12 inches long and not know that it’s going to live 40 years and grow to 10 feet," he said. The aquarium gets so many calls from people whose sharks have outgrown their tanks that it can’t take them all. Pet sharks, he added, shouldn’t be released into the wild.

Monique Samuels installed a 875-gallon tank in her kitchen in Potomac, Md. It’s home to Horney, a horn shark, and a two-foot-long sand shark she named the Grande Dame. (She later discovered it’s a male, but said she’s not planning to change the name.)

Monique Samuels with the shark tank in her Potomac, Md., home. Chris Samuels

"They’re my babies," said Ms. Samuels, who stars in the reality television show, "The Real Housewives of Potomac."

The tank, plus the sharks and other fish that live there, cost about $60,000, she said. She had to install a steel support stand in the cabinet that holds the 9-foot-long tank, which is so heavy it required six people to bring it inside, Ms. Samuels said.

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The family also spends roughly $1,600 to $2,000 each month on maintenance and food, like frozen krill and shrimp.

That brings up another downside: the biting.

Feeding times are perilous for the tank’s other inhabitants. For aesthetic purposes, most people like to have other species in their tanks alongside sharks. Mr. Caparatta, the Manhattan Aquariums owner, said "it’s really just a matter of time before they eat some of the other fish…We’ve had expensive fish chomped in half."

Horney the horn shark. Monique Samuels

One of the Samuels’ other fish, a sailfin tang named Stripe, died after being bitten by a shark during a feeding frenzy. "He got caught right in the middle," Ms. Samuels said. After the bite, "you could see a gash—it was pretty gruesome."

Mr. Caparatta offered advice for keeping other fish in the tank safe, though his plan isn’t exactly foolproof. "As long as you keep the sharks well-fed, there’s a good chance that they won’t eat their tank mates," he said.

He had simpler instructions for shark owners who "like to hand-feed" the sharks by holding a piece of meat above the water.

"We recommend using tongs," he said.