Leafy sea dragons, foot-long fish with flowy and fernlike fronds, typically lead what appears to be a very chill existence.
In their native Australian waters, they float with the current, avoiding predators by looking more like stray seaweed than flesh. To fill their bellies, they suck tiny crustaceans off the ocean floor through a columnar snout similar to those of their sea horse relatives.
“They sort of hover like an astronaut,” said Ari Fustukjian, a veterinarian at the Florida Aquarium in Tampa.
So Fustukjian and his colleagues knew something was wrong when three leafy sea dragons the aquarium acquired this spring from Australia were sinking. The juvenile fish, whose sexes still have not been determined, were using all their energy in futile attempts to stay above the floor of their habitat. They were eating poorly. If something didn’t change, Fustukjian said he knew, the trio would die.
X-rays soon revealed that their swim bladders – air sacs in some fish that regulate buoyancy – were “almost absent,” Fustukjian said. “Somewhere along the normal developmental process, these guys missed the bus.”
The good news was that they were otherwise healthy, so finding a way to make them buoyant would solve the problem.
And that’s how Fustukjian came up with tiny sea-dragon floaties.
The fixes were black rings that loop around the animals’ midsections like life preservers and are made of neoprene, which provides buoyancy, is soft on a sea dragon and can withstand saltwater.