From a distance, they look like colorful seaweed, drifting in the Minnesota Zoo’s new 800-gallon tank.
But up close, delicate, rare leafy sea dragons are exposed for what they are: long-snouted cousins of seahorses that hide among the weeds they resemble.
The Apple Valley zoo placed two species of sea dragons — leafy and weedy — in their new home in Discovery Bay this week. The zoo is the only facility in Minnesota to own leafy sea dragons, aquarist Dan Peterson said.
The new tank cost about $25,000, Peterson said, and the animals an additional $25,000.
Two leafy sea dragons and a handful of weedy sea dragons are on display. The zoo previously had weedy sea dragons but displayed them in a much smaller tank.
“We always wanted to have the leafies, but we didn’t have a big enough tank,” Peterson said.
Both types of sea dragon — sleek weedy dragons are black and vibrant yellow with shorter, less fragile-looking appendages — are exhibited together. Sea dragons live off the southern coast of Australia, where they are listed as being near-threatened.
Because of their status, one person in Australia is authorized to collect a pregnant male (like seahorses, male dragons carry the young) weedy sea dragon once a year. After the eggs are hatched, the adult is returned to the wild. The babies are then distributed to aquariums and zoos on a waiting list to receive them. Each leafy sea dragon costs about $3,500 plus shipping.
The leafy dragons arrived at the zoo about 11 months ago, Peterson said, and awaited completion of their new home in an off-display holding tank.
When the dragons first arrived, Peterson said, they would eat only fresh mysid shrimp. Zoo workers had to train them to eat much less expensive frozen food.
“For what it costs to feed them live shrimp for two weeks, we can feed them frozen for the whole year,” Peterson said.
The high-maintenance creatures prefer cold water — their tank is kept at 58 degrees. There’s an alarm on it in case the cooling system should fail, Peterson said.
“If the chiller went out, they could get sick or die,” Peterson said.
Zoo workers also have to siphon their tank daily to minimize the risk of disease.
Peterson said he hopes the dragons eventually will breed. Weedy sea dragons have been bred in aquariums in Long Beach, Calif., and Tennessee, but no leafy dragon has bred in captivity.
“That’s kind of the ultimate goal — to breed them,” Peterson said. But he admitted breeding the leafy dragons was a long shot. Sea dragons have been held in captivity only since the 1990s, and he said it was hard to say if aquarists were “missing something” in their requirements for breeding.
The notorious sensitivity of the sea dragons is one reason not many aquariums or zoos have them, Peterson said.
“They’re delicate and temperamental,” Peterson said. “At times, it seems like if you look at them wrong, they don’t want to eat anymore.”
Jessica Fleming can be reached at 651-228-5435.
