BIDDEFORD – A University of New England researcher is working to breed a tropical aquarium fish in captivity in an effort to take pressure off fragile ecosystems in Southeast Asia that are being damaged by unsustainable harvesting of exotic fish species.

Jeri Fox is raising a pair of foxface rabbitfish in a tank in a basement lab at the university. The fish are distinctive with bright yellow fins, bulging eyes and puckered lips.

Trading in tropical aquarium fish began in the 1930s in Sri Lanka. The modern industry, estimated to be worth at least $200 million annually, still relies heavily on poor coastal communities in Southeast Asia.

While the trade can provide good jobs in depressed areas and can contribute to the conservation of coral reefs, many harvesting practices are thought to be unsustainable, according to a 2003 United Nations report.

The report cites problems such as overfishing, the collection of live rock, and the use of sodium cyanide to stun and catch fish. Also troubling is the destruction of coral reefs, which support one-third of the planet’s marine fish species, the report says.

“The aquarium trade will continue. It’s not going to stop,” Fox said. “So we want to supply it with fish that are raised, not destructively removed from the wild.”

Efforts are under way to change how the fish are caught. In 2001, the Marine Aquarium Council, a nonprofit organization based in Honolulu, introduced certification standards for shippers and importers. It also is working with fishermen in Indonesia and the Philippines to develop fishery management plans.

At the same time, some scientists are successfully breeding certain aquarium fish in captivity. In Terre Haute, Ind., Dan Denker raises clownfish, seahorses and coral.

Denker said that growing coral outside the ocean helps marine ecosystems because it reduces the demand for naturally occurring coral, which supports a host of underwater species.

“It does take stress off the oceans,” he said.

But only a small percentage of the roughly 1,500 tropical fish species traded worldwide have been bred successfully in captivity, and the foxface rabbitfish is not among them.

A key reason is the fish’s small size, only about 2 millimeters at spawning. The fish’s mouth is no more than half a millimeter wide, making it difficult to provide appropriate food.

Breeding tropical fish involves reproducing the species’ spawning conditions as closely as possible. That can mean analyzing the protein content of the fish’s eggs to try to replicate its diet, and using lights to simulate the lunar cycle.

The process can be painstaking, and some scientists have been trying to breed the same species for 15 years, said Fox.

The foxface rabbitfish is not being taken from the ocean in a conscientious way, she said, which makes it a good candidate for captive breeding.