Fish therapy is a booming business in China, with sales soaring from $6 billion in 2016 to more than $13 billion in 2017, according to market research firm Global Fish.
But the fish treatment business has been on the decline in the U.S., according to a new report from research firm CB Insights.
In 2016, fish therapy sold $7.8 billion in U.K. retail outlets, according for CB Insight.
That was down 22 percent from $10.6 billion sales in 2017.
That is a 17 percent decline.
But the market for fish therapy in the United States has grown in the past five years, according CB Ins, which compiled the report.
Fish therapy was a $1.9 billion market in 2016, but fell to $2.1 billion in 2018.
The biggest growth came in 2017 from the use of high-tech fish tanks to treat fish with cysts, the report said.
That year, the use increased from 3.3 percent of total fish therapy sales to 5.1 percent.
As a result, the fish industry is seeing an increase in the number of fish therapy facilities.
CB Ins also said that in 2017 fish therapy increased to 5,500 out of an estimated 20,000 in the country, which is a 30 percent increase from 2016.
The report said that fish therapy has been growing in the Chinese market because of its cost-effective treatment, while the U to U cost of treatment is also cheaper.
The fish therapy market in China is expected to reach $12 billion by 2021.