“A fish with a glass eye” sounds like the punchline to a joke that starts with an angler and an optician walking into a bar.
But two rockfish at the Vancouver Aquarium in Canada are now sporting bright yellow ocular prosthetics, thanks to a technique honed in Seattle, USA, the Bulletin reports.
The fish, who each lost an eye to disease, were restored to their former good looks by the operation. The primary goal, however, was to prevent them from being harassed by other fish, which seem to view an empty eye socket as a sign of weakness, said Seattle Aquarium veterinarian Dr Lesanna Lahner.
“There’s an aesthetic piece, but my main concern is fish health,” said Dr Lahner, who has been fine-tuning the procedure over the past few years.
A handful of fish at the Seattle Aquarium have received the implants, and Dr Lahner assisted Vancouver vets with their one-eyed rockfish last month.
The staff at the British Columbia aquarium was very worried about a copper rockfish that had an eye surgically removed after a cataract rupture. The 6-pound fish started avoiding its tank mates and hiding in nooks and crannies, said Dr Martin Haulena, the aquarium’s head veterinarian.
“Fish were picking at it,” he said. “Its fins were tattered, and it was really getting banged up.”
With life spans that can exceed a century in the wild, quality of life is particularly important for captive rockfish.
During the 20-minute procedure, a technician bathed the anaesthetised animal’s gills and skin with water, while Dr Lahner popped the prosthetic into the socket and coached Dr Haulena on the best way to thread fishing line through bone to hold it in place.
The glass eyes are the kind taxidermists use in trophy trout and salmon mounted for display. Dr Lahner glues two of the flat-backed inserts together to form a sphere.
Fake eyes for fish aren’t new, she pointed out.
The idea was pioneered in the 1990s by Drs Craig Harms and Greg Lewbart, Dr Lahner’s mentors at North Carolina State University. They developed a surgical procedure tailored for ornamental koi. Collectors will pay tens of thousands of dollars for a single, exquisitely patterned specimen, and there’s little tolerance for one-eyed fish in an industry built around beauty.
Dr Lahner adapted her mentors’ method to work in cold-water species, eliminating an adhesive that can cause inflammation and devising a way to anchor the prosthetic with fishing line and titanium clips.
“It’s still a work in progress,” she said. “I would not say by any means this technique is perfected.”
Fish with a missing eye used to be routinely euthanised at aquariums because they were considered unsightly, Dr Haulena said.
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(IAF1501)
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