Nishikigoi carp are gaining popularity overseas as an ornamental pet as Japanese breeders step up efforts to boost exports in the face of dwindling domestic demand.

In early February, one of the largest Nishikigoi competitions in Japan was held in Tokyo with 1,800 carp presented in the two-day event, drawing a crowd of some 5,000 people from Japan and abroad.

A Nishikigoi can fetch tens of millions of yen depending on its size, form and color patterns.

A man from Malaysia at the event said he keeps hundreds of Nishikigoi at a Japanese garden at his home in Kuala Lumpur as he finds the fish "elegant" and pleasant to watch.

Now that building a pond in a home garden is a declining tradition in Japan, more than a half of the Nishikigoi put on the market by Japanese producers were bought by overseas buyers, according to All Japan Nishikigoi Promotion Association headquartered in Ojiya, Niigata Prefecture.

The government of Niigata, the birthplace of Nishikigoi breeding and where half of the nation's carp breeders are gathered, estimates the prefecture's exports of the fish totaled 2.35 billion yen in 2016, up significantly from 1.42 billion yen in 2012 when it started keeping records.

While European countries such as Netherlands are major importers of Nishikigoi, sales to Asian nations such as Thailand and Indonesia are growing in recent years, it said.

"In places like Southeast Asia and Hong Kong, a carp is considered to bring good luck and ones with red and white color patterns are particularly popular," says Hideo Nishiwaki, executive director of the association.

Carp breeders in Niigata are trying to attract more overseas buyers by stepping up promotional activities including holding seminars on how to keep the fish.

Among such breeders, Isa Koi Farm in Ojiya says some 80 percent of its Nishikigoi are sold abroad.

"I want people around the world to know more about the charm of Nishikigoi," said the farm's president, Mitsunori Isa.