Shawn Garner watches over 18 tanks of hundreds of tiny sea horses, bobbing among the artificial sea grasses and plastic zip ties provided to give their tails a hitching post.

“It’s the coolest animal in the world,” he said, showing them off with a touch of both pride and awe. “It has a head like a horse, a tail like a monkey and a pouch like a kangaroo.”

Garner, supervisor of the Mote Marine Laboratory’s sea-horse conservation lab, is one of several experts across the country trying to raise ornamental fish and other wild marine species in captivity. These researchers, many working at aquariums and zoos, are engaging in the kinds of farming operations once reserved for fish sold in food markets and restaurants.

For sea horses, the stakes are high. Nearly one-fourth of the 36 sea-horse species assessed by the International Union for Conservation of Nature are threatened with extinction.

Three factors account for the deaths of tens of millions of sea horses each year: the Chinese medicinal trade, accidental catch by shrimp trawling and other fishing operations, and habitat destruction.

“Being able to breed and raise sea horses is one part of the solution. Unfortunately, it’s not the only solution,” said Heather Koldewey, head of global conservation programs for the Zoological Society of London, adding that fishing restrictions and other coastal protections are also essential.

Before the 1990s, sea-horse farming was plagued by problems. Sea horses live in low densities in the wild — in many parts of the world, including the western Atlantic from Canada to South America and in Southeast Asia — so crowding them into a tank can stress them and lead to disease. Researchers in several countries — primarily the United Kingdom, the United States and Australia — have made strides in the past couple of decades, though reproducing the animals remains challenging.

The staff at the Birch Aquarium at the Scripps Institution of Oceanography in La Jolla, Calif., which has raised 12 sea-horse species, found that a tank usually used for jellyfish worked better than rectangular ones. The tank contains a slice of cylinder sandwiched between the two sides, and the baby sea horses were inside the cylinder, which kept them from getting trapped at the top edges because of poor water circulation.

“That really changed things for us,” said the aquarium’s co-curator Leslee Matsushige.

Mating habits

It probably doesn’t help captive breeders that sea horses — already unusual because the males carry the young and give birth — aren’t promiscuous and instead live in bonded pairs.

“They do flirt a lot, but they’re actually faithful,” said Koldewey, who also serves as field conservation manager for Project Seahorse. “There’s a lot of behavior to suggest otherwise, but if you do the genetic analysis, it’s just all show.”

Aquarists have also made some breakthroughs with sea dragons, which are related to sea horses but differ in several aspects, including the way they move and use their tail. There are just two species — leafy and weedy, named for their form of camouflage — and they live in the temperate waters off Australia. The Aquarium of the Pacific in Long Beach, Calif., became the world’s first to breed weedy sea dragons in 2001, from a progenitor named “Big Daddy,” but it only repeated that feat once, in 2003.

Perry Hampton, the aquarium’s vice president of husbandry, said his team has mimicked the sea dragons’ natural environment through water temperature and light exposure, but they can’t force the animals to mate. “Right now, the ball’s in their court.”

Scripps professor Greg Rouse recently received a $300,000 grant to launch the first-of-its-kind sea-dragon breeding pilot program with the Birch Aquarium.

For the most part, aquariums — including Mote, Birch and the Monterey Bay Aquarium — raise sea horses to populate exhibits and raise public awareness of the animals’ predicament. Some innovators hope to either sell marine species to offer an alternative to wild-caught ones or reintroduce them to the wild to boost their numbers.

The Aquarium of the Pacific, for example, is working with federal officials to propagate endangered white abalone, as well as the Micronesian kingfisher bird.

And SeaWorld Parks & Entertainment in Orlando has launched the Rising Tide Conservation program, which aims to promote captive breeding of ornamental saltwater fish to ease pressure on the world’s coral reefs. Many of the saltwater fish sold in the aquarium trade are wild-caught, collected through destructive practices such as dynamite and cyanide fishing, because it is cheaper and easier than raising them.

The program, which started collecting eggs from 20 species in large reef displays in U.S. zoos and aquariums in 2010 and 2011, has raised six species. Working with the University of Florida’s Tropical Aquaculture Laboratory, the program aims to teach what it’s learned to commercial fish-farming operations so they can raise those species, such as semicircle angelfish and smallmouth grunt.

Judy St. Leger, who oversees the program and serves as SeaWorld’s director of pathology and research, said many commercial operators stopped researching once they mastered the art of raising clown fish and other popular species. She and her collaborators, by contrast, “realize that this is not a problemthat can be resolved in one or two years. We’re prepared to be working on it for 10 or 20 years. . . . We’re prepared to keep going in order to make a difference for the reefs.”

Although ornamental-fish farmers face some different obstacles than sea-horse breeders, such as figuring out what tiny live food the microscopic ornamental larvae will eat, they both face the challenge of competing in an open marketplace. In the Chinese medicinal market, dried wild sea horses fetch higher prices than cultured ones; U.S. hobbyists are willing to buy farm-raised fish, but they can cost four to five times as much.

Dustin Dorton, who works with Rising Tide and sells farmed saltwater fish as president of Oceans, Reefs & Aquariums, said he remains optimistic the price differential will narrow with a few big breakthroughs.

“There’s just no way the hobby trade is going to be able to continue harvesting fish at whatever pace they desire in the future,” Dorton said.

An amazing sight

Garner saw a sea horse for the first time at a pet store in South Bend, Ind., when he was about 17, after growing up on Indiana’s largest palomino farm. The tiny creatures were unlike anything he had seen.

“Seeing it in real life was amazing,” he recalled. “Especially their eyes. I love watching their eyes, because they move in all directions. And their tails, what’s up with that?”

He started raising corals as a hobby and became so successful that he used corals, and then clown fish and sea horses, to help put himself through Ball State University.

Today, at 31, he has already developed several innovations to boost sea-horse breeding and survival rates, using plastic funnel cone feeders with a tiny hole at the bottom that slowly releases the brine shrimp sea horses need. He also exposes baby sea horses to light 20 hours a day, to keep them feeding.

He hopes to publish a book about his farming techniques so that others can copy them and has contemplated trying to break into the Asian medicinal market. For now, however, he’s focused on perfecting his skills to supply aquariums with as many sea horses as possible.

“Every aquarist needs one animal to really love, and to work with, and they’re mine,” he said of sea horses.