Is it wrong to keep octopuses in captivity?

Cephalopod experts worry that trade is putting pressure on some alluring species.

“I get asked all the time, ‘Can you get octopuses?’” says Jeff Slemp, proprietor of a store called Cuttlefish and Corals Sustainable Saltwater Aquariums, in Portland, Oregon. Slemp isn't opposed on principle to keeping these big-brained, unusually smart mollusks as pets, but he won’t sell octopuses to just anyone. “We have to make sure they have the background, make sure they have the knowledge to treat the things that pop up."

One of those pop-ups is the octopuses themselves. Because they’re solitary, they can fare better in captivity than animals whose rich familial and social lives can’t be reproduced there—as long as they're provided a suitably rich environment. They’re master escape artists, able to slop through thin cracks and out of all but the most securely sealed tanks—one of many traits that make them uniquely challenging and costly animals to keep.

Such traits make octopuses stars of the page and screen. A slew of research papers, popular books, magazine articles, and nature documentaries celebrates their improbable intelligence (a mollusk with a vertebrate-size brain and problem-solving ability!), their protean shape- and color-shifting, even their playfulness and idiosyncratic personalities.

Just this month, the season premiere of PBS’s Nature series, "Octopus: Making Contact," told the endearing tale of the close relationship between an Alaskan professor and his daughter and their pet octopus. In Seattle, the artists, writers, musicians, and scientists of the Cephalopod Appreciation Society gather each summer to celebrate octopuses and their squid and cuttlefish cousins in image, word, and song.

And at aquariums around the world, octopuses are reliable crowd pleasers. The Seattle Aquarium holds an annual Valentine’s Day party to mark the would-be mating of its giant Pacific octopuses (the world's largest species, sometimes weighing more than 100 pounds, with an arm span of up to 20 feet).

“Octopuses are very charismatic,” says James Wood, a marine biologist turned aquarium operator based near Palm Beach, Florida. “It’s cool now to be a nerd, and they’re the ultimate nerd animals.” So it’s only natural that ardent aquarium hobbyists and newly sea-struck fans alike may get the urge to have their own eight-legged marvels. “Reading all the articles out there, people see themselves in these animals,” says a salesman at one leading marine-animal importer, who asked not to be named because he spoke without authorization.

Even so, it’s unclear whether all the fascination is hurting octopuses. That’s partly because records of imports of cephalopods to the United States are spotty and out of date. Wood and other experts fear that too much enthusiasm may endanger two of the most dazzling and mediagenic, but little studied and potentially rare, species: the striped or wunderpus octopus (discovered in the 1980s) and its cousin, the mimic octopus (identified only in 1998). And they worry about the danger posed to naïve hobbyists by the alluring, but lethally venomous, blue-ringed octopus.

Wunderpus and mimic octopuses are the ultimate quick-change artists, hiding in plain sight by impersonating everything from rocks and seaweed to sea snakes and lionfish. They quickly became the darlings of the nature programs. But much remains unknown about them, especially about mimics, including how many inhabit the shallow seabeds off Sulawesi, Indonesia, and other Indo-Pacific islands where they’re found.

Vendors and importers sometimes conflate the two species, but that doesn’t stop them from offering both to collectors willing to pay $200 or more for one. Demand in the U.S. seems to have begun growing in the few years for which official import data have been released, although the numbers were small. One import of a mimic was recorded in 2008, two in 2009, and 30 in 2011, the last year available.

Even if that demand continued exponentially, it would be legal: None of the 300-plus known species of octopus is listed under the Convention on International Trade in Endangered Species of Fauna and Flora (CITES), which regulates cross-border trade in wildlife, or the U.S. Endangered Species Act (ESA). This may reflect a lack of information—for example, in the case of the mimic octopus. On the Cephalopod Page website, which Wood edits, aquarist Christopher Shaw and University of California, Berkeley, biologist Roy Caldwell posted a package of articles under the headline, “Mimic Octopuses: Will We Love Them to Death?”

“If there is one thing that we know about mimics,” Shaw writes, “it is that they are rare.” He notes that their Indonesian coastal habitat is being wiped out by runoff and mining and that they do poorly in captivity, which means many mimics likely die so one can survive a few months in a tank. He urges even public aquariums to resist the lure of this trophy: “I honestly fear that if we cannot stem their collection, there will be no mimics to wonder at in a very few years.”

Fatal attraction

Another celebrated octopus presents a different concern. All octopuses probably carry some venom, but only the various golf ball-size blue-ringed species, which range from southern Japan to Australia, are known to pack a lethal dose. Their saliva contains the potent nerve toxin tetrodotoxin, the same compound that makes California newts, harlequin frogs, and fugu pufferfish liver so deadly. One blue ring can carry enough to kill 10 or more humans.

Blue-ring bites occur each year in Australia, but timely, vigorous artificial respiration usually prevents fatalities; only three have been confirmed during the past century, none involving aquariums. More blue-ring fatalities may go unidentified, however, because the bites are painless and the mode of death—respiratory paralysis—can be caused by other toxins and nerve, muscle, and lung conditions.

Caldwell recounts a close escape. He had recruited his teenage daughter to help him scour reef samples for the mantis shrimp he was studying off Australia's Lizard Island. She felt "something soft and squishy" inside one rock oyster shell. "I assumed it was a small sea cucumber and dismissed the comment," he writes on the Cephalopod Page. But when he cracked the shell open, "a tangle of arms covered with small iridescent blue spots spewed from the fissure,” he wrote on the Cephalopod Page. Rather than crawling for cover like most octopuses, [the octopus] reared up while pulling back her first two pair of arms [and] exposing her mouth. It was very clear to me that here was an octopus ready to bite.... This was a potentially lethal blue-ringed octopus that my unsuspecting daughter had handled just minutes earlier."

Blue rings’ lethality, coupled with their dazzling eponymous markings, exert a powerful allure on some aquarium aficionados—“daredevils,” Slemp calls them. Imports of blue rings to the U.S. grew steadily during a recent period, outpacing all other octopus species: 11 were documented in 2004, 348 in 2008, 494 in 2009, and 1,148 in 2011. Those almost certainly weren’t the only blue rings that came in. “Sometimes they hitchhike along on [chunks of coral reef], and you don’t even know you have one,” Wood says.

“I’ve seen them in pet shops and home aquaria where owners didn’t know what it was,” Slemp says. He thinks keeping blue rings is “a really bad idea” and refuses to sell them. “Octopuses escape. So now you’ve got something that’s potentially deadly, that’s pretty, that children are attracted to, on the loose.”

Other vendors still offer them, even online. One, Pete’s Aquariums in Fishkill, New York, lists blue rings at $199.99 but notes that they’re sold out. The store’s receptionist hung up abruptly when I identified myself and asked about their blue rings.

'Not an animal to be taken on lightly'

The growing public fascination with octopuses doesn’t seem to have translated into surging sales—so far, anyway. "If anything,” says the sales manager at one aquarium-animal import company who requested anonymity because he was speaking without authorization, “I’ve seen a downturn over the years."

This may be in part because some aquarium shops have stopped what Rich Ross, a former senior biologist at San Francisco's Steinhart Aquarium calls “supermarket-style” stocking of exotic pets. (Ross is now with the Albright Laboratory, a coral-reef research and restoration facility affiliated with the aquarium.) Instead, they’re adopting custom ordering, which reduces excess shipments of animals and therefore mortality. Custom ordering also enables responsible vendors to evaluate purchasers and advise them about best practices.

Any downturn also reflects the efforts of Wood and other experts to educate hobbyists and vendors about the costs and hazards of keeping these demanding super-mollusks. In addition to their high prices and expensive diets—heavy on live crabs and shrimp— octopuses need large, escape-proof tanks with ample hiding places, unassailable fixtures to withstand their powerful arms and inquisitive tampering, and no fish or other companions (they'll eat them).

“It can cost a couple thousand dollars just to get set up," says Reyna Bueno, of Barrier Reef Aquariums, a leading Seattle-area vendor.

The purchase is also a short-term investment. Most species live only one to two years, and a newly imported octopus may have just weeks left. Some robust common species, such as the California two-spot octopus, get along relatively well in captivity. Others, such as the fabled but delicate mimic, do much worse. (The mimic is also reclusive and nocturnal and unlikely to display its famous shape-shifting in a tank.)

“Word got out,” Ross says. “This is not an animal to be taken on lightly.” The fact that octopuses seem very intelligent deters some people, who have qualms about treating them badly, from buying them. But, Ross adds, some conspicuous aquarium keepers accept the high costs and turnover as the price of displaying such charismatic creatures: “They think of these animals as cut flowers."

Such cavalier attitudes trouble Wood, who studied octopuses as a faculty member at the Bermuda Institute of Ocean Sciences. He found that these intelligent, curious animals need more than space, food, and clean water.

“All the reasons you would use enrichment for vertebrates apply to octopuses,” Wood says. When he began his research, he kept his octopuses in bare containers. “Some would crawl up the containers, out of the water, and just dry out. Some would eat their own arms,” he says. When Wood enriched their lives, adding “things to crawl into and explore, those self-destructive behaviors stopped.”

Some animal advocates believe that such creatures shouldn’t be kept in aquariums at all. "Life in a tank is no life at all for sensitive, intelligent octopuses," declares People for the Ethical Treatment of Animals. The organization cheers the celebrated flight of an octopus called Inky from New Zealand's National Aquarium in 2016: "His bold escape should send a message to aquariums to keep their tentacles off octopuses for good."

University of Lethbridge animal psychologist Jennifer Mather, a pioneering researcher into octopus cognition and personality, sees octopuses as "the poster child for invertebrate animal welfare"—worthy of the same rights as animals that look more like us. Aquarium hobbyists can be allies in this cause, she argues, contributing to public and scientific understanding of these previously overlooked animals: "When people keep octopuses at home, they really get an attachment to them, and share that appreciation."

'A data vacuum'

To determine whether and how imports of octopuses and other aquarium species are affecting wild populations, it would help greatly to know just how many are being imported. But trade volumes and trends are largely matters of anecdote and speculation.

"We are in a data vacuum," says Andrew Rhyne, a biologist at Roger Williams University, in Bristol, Rhode Island. "The U.S. and other countries do not have any system in place to monitor the trade and provide data" for wildlife, such as octopuses, not listed under CITES. (See what happened at the most recent CITES conference.)

The U.S. Fish and Wildlife Service, which regulates the nation’s wildlife trade, requires that import declarations be filed for all species coming in, as well as a more detailed invoice for each wildlife shipment. The service uses the volume of shipments received to determine staff needs and resources at the nation’s ports of entry. But it doesn’t compile import counts for octopuses and other unlisted species or readily release information from the invoices.

Rhyne and his team, however, were able to partially fill the data vacuum. The National Oceanic and Atmospheric Administration (NOAA), by agreement with the Fish and Wildlife Service, obtained the invoices for imports of aquarium species during three complete years (2008, 2009, and 2011) and parts of 2004 and 2005. NOAA funded Roger Williams University's Marine Aquarium and Biodiversity Trade Flow project to digitize and analyze the information in them

The result was a suggestive snapshot of the marine wildlife trade into the U.S., but even this small trove of data—all that we have on octopus imports—is outdated and imperfect. Rhyne's team found many discrepancies between the import declarations and the more detailed invoices.

Biologist Rich Ross, who once worked in the commercial aquarium trade, proposes a private-sector solution to the information drought: “a cooperative of responsible saltwater aquarium dealers” that could both track the trade and promote sustainable practices. It would be something along the lines of various angler's groups and the Association of Zoos and Aquariums, which represents public institutions.

James Wood also hails the idea. But Ross acknowledges that it hasn’t been easy to rally the industry; two previous efforts failed.

Meanwhile, Ross warns, the apparent recent lull in octopus imports could reverse at any time, especially because most of the species people want, including mimics and wunderpuses, come from weakly regulated collectors in Indonesia and the Philippines—the Wild West of marine wildlife collecting. "It's completely possible we will see an influx," he says.

Eric Scigliano's books include Puget Sound: Sea Between the Mountains, Love War and Circuses (Seeing the Elephant), Michelangelo’s Mountain, Flotsametrics and the Floating World (with Curtis Ebbesmeyer), The Wild Edge , and, forthcoming, The Big Thaw: Ancient Carbon and a Race to Save the Planet . Follow him on Twitter.
Wildlife Watch is an investigative reporting project between National Geographic Society and National Geographic Partners focusing on wildlife crime and exploitation. Read more Wildlife Watch stories here, and learn more about National Geographic Society’s nonprofit mission at Send tips, feedback, and story ideas to

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