A Popular Coral for Home Aquariums Can Release Deadly Toxin

The coral produces a toxic mist that can cause serious health problems

Neil Skene via Wikimedia Commons

When a man stumbled into an emergency room in an Anchorage, Alaska hospital on August 12, 2014 suffering from a high fever, pain and with a metallic taste in his mouth he had an unusual guess for the culprit. He suspected that he had been poisoned by a coral in his bedroom aquarium.

According to a recent report published in the Centers for Disease Control's Morbidity and Mortality Weekly, a brightly-colored aquarium coral has been responsible for poisoning at least 10 people in Anchorage, Alaska over the last several years. Zoanthid corals are some of the most common corals found in aquariums, but despite their beauty, some kinds can produce a chemical called “palytoxin,” a substance that can cause fever and a whole range of breathing, muscle and neurologic problems. But while the toxin is most easily transmitted through direct contact with the corals, it appears that zoanthids can also extrude palytoxin through what Scientific American’s Jennifer Frazer calls “a creeping death mist.”

The patient recalled that the day before he wound up in hospital with palytoxin poisoning, one of his housemates had brought home and transferred a zoanthid coral into a home aquarium in his bedroom. While no one affected had touched the coral, the CDC reports that the patient and one of his roommates “noted a visible mist and sensed humidity in the mobile home on the morning after coral introduction, leading them to suspect a possible problem with the aquarium.” As Frazer writes:

The next morning, all three [housemates] awoke with a nasty suite of neurologic, breathing, and muscle problems. The man who'd slept in the room with the aquarium was worst off. His fever had reached 103°F and his white blood cell count was elevated. He spent two days in the hospital before recovering.

The CDC researchers believed that the roommates were poisoned by a few small coral fragments that snapped off and fell to the ground while it was being transferred into its tank. On further investigation the CDC researchers discovered several employees of the pet store where the man’s roommate had bought the coral had suffered palytoxin poisoning over the last two years. One employee reported experiencing symptoms nine times in the last year alone, Rachael Rettner writes for Live Science.

"Many aquarium store employees and marine aquarium hobbyists are not aware of palytoxin as a potentially serious hazard associated with handling some zoanthid corals," the CDC researchers report. "General recommendations on coral handling and decontamination practices would be helpful for hobbyists, commercial coral growers, and the public health and clinical provider communities."

Coral are certainly still pretty to look at, and a little extra care could save aquarium hobbyists a trip to the hospital.

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