An Injured Moray Eel at a South Carolina Aquarium Receives Unusual Medical Treatment

Eel in CT Scan
Courtesy MJ Green
A sedated green moray eel from the South Carolina Aquarium undergoes a CT scan.

As an aquarist at the South Carolina Aquarium in Charleston, S.C., Jason Cassell spends much of his day simply observing. “I’m in the tank with the animals for hours at a time, so I get to know their habits, movements, and postures,” he says. So, last month, when the aquarium’s green moray eel was having a hard time turning his head, and was favoring one side when swimming, Cassell knew something was wrong. Suspecting a spinal injury, the aquarium’s veterinarian, Dr. Shane Boylan, brought the eel to the Charleston Veterinary Referral Center (CVRC) for a CT scan.

The six-foot-long, 50-pound eel was netted, placed in a transport tank, and driven to the clinic on the back of a flatbed truck. Once at CVRC, staffers puzzled over how to perform the CT scan without getting attacked. “They’re actually very docile animals that would rather hide,” says Dr. Jason King, a neurologist at CVRC. “But if they feel threatened, they will come after you.”

He says that there are several dangers with this species, including the fact that they secrete toxin-filled slime to protect their skin. "When we handled the eel, we wore gloves to avoid getting burned by the slime,” he says. An even bigger danger is getting bitten, since the moray eel has long, sharp teeth designed to tear flesh.

If that weren’t intimidating enough, the creature also has a concealed weapon — a second set of jaws, located in its esophagus. Once the moray eel secures its prey with the first set of jaws, its pharyngeal jaws shoot up from the throat, grabbing and pulling the prey down into the esophagus. “It’s a lot like the monster in the movie Alien,” says Dr. King. “So there is real danger.”

To guard against such mishaps, Dr. King anesthetized the eel by adding a chemical to the water in the transport tank. As soon as the eel fell asleep, he was placed on the CT scan couch. “We figured we had six or seven minutes to complete the scan before we had to return him to the water,” says Dr. King.

Eel on Scanner
Courtesy MJ Green
Dr. King analyzes the eel's scans at the Charleston Veterinary Referral Center.

Within just five minutes, the CT scan produced 441 images of the eel, encompassing four feet, from his nose down to his back. After reviewing the images, Dr. King determined that the eel had suffered a spinal cord compression. “If it were a dog or a cat, I would determine that it was most likely caused by a ruptured disc,” he says. “This seems to make the most sense in this case, too.” It’s difficult to pinpoint exactly what caused the rupture, but Dr. King suspects the eel may have either gotten stuck in something or was rammed by a fish. Now that they had a diagnosis, Dr. King had to decide how to go about treating the injury. “With a dog or a cat, I'd recommend surgery to resolve the issue more quickly,” he says. But he chose a more cautious approach with the eel. “I certainly don’t want to put this animal at any more risk than we absolutely have to,” he adds. “Neurosurgery is a big deal for a person, a dog or a cat, but it's especially true for a fish.”

Along with the fact that he’s navigating uncharted territory, Dr. King says the moray eel’s anatomy makes surgery a major challenge. “I don’t even have a rib to count from, and there’s a lot of vertebrae in this animal,” he explains. “Finding a place to get into the vertebral canal would be tricky, to say the least.”

Moray Eel in Water
Courtesy MJ Green
The vibrant green moray eel is happily on the mend now.

Although he doesn’t rule out surgery down the line, Dr. King determined that the best course of action was to keep the eel calm, quiet, and confined to see if he would heal on his own. Since eels like to hide in burrows, the aquarium set up a long PVC pipe for the animal to live in, which was placed inside a small tank. The aquarium’s aquarist feeds him using a set of tongs, so the eel doesn’t have to move too much.

It’s been two weeks since the CT scan and the aquarium staff has already seen some improvement. “He’s moving his head around a little more, and posturing like he wants to eat,” says aquarist Jason Cassell.

While Cassell appreciates the eel’s contribution to veterinary medicine, he mainly just wants his companion to get better. “He’s a pleasure to work with,” he says. “If I’m scrubbing the tank, he’ll swim up right next to me and watch. He’s a fantastic animal.”

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