"Some fish are completely unsuitable to aquariums," said Ed Green, one of the report's authors, adding mishandling of the rare fish often started very early in the supply chain.

"Some fish are just treated as disposable commodities, exposed to the sunlight for hours after being caught and stored in plastic bags on their long journey from Southeast Asian reefs to aquariums in North America and Europe," he told Reuters.

He said there was no indication that the aquarium trade was threatening any species with extinction, although some harvesting methods, like stunning the fish with a near-lethal dose of sodium cyanide, could harm both fish and coral reefs.

About 50,000 people in Sri Lanka are directly involved in the export of marine life, a business which also provides a strong incentive to preserve fish stocks and reef environments.

The report recommends the wider application of certification schemes by the Marine Aquarium Council (MAC), an international not-for-profit organization. Green said parents buying fish for their children should also pay more attention to their origin.

The sale of clown fish shot up this year because of the movie "Finding Nemo," a computer-animated tale of a clown fish who ends up in a dentist's aquarium.