Customer backlash has Chilean farmed salmon producers promising to reduce the use of antibiotics in fish farms by half by 2025.

Members of the Chilean Salmon Marketing Council made the announcement last month at Seafood Expo North America in Boston. The group will work with the Monterey Bay Aquarium’s Seafood Watch program to secure a better rating in an effort called the Chilean Salmon Antibiotic Reduction Program (CSARP).

Chile is the world’s second largest producer of farmed salmon after Norway and most of the farmed salmon that Americans buy comes from Chile.

Chile was court ordered three years ago to disclose its antibiotic use after 37 companies refused to give any details, saying it would pose a “competition and commercial risk.”

Chilean fish farmers use florfenicol, a common veterinary antibiotic, to kill a bacteria that causes lesions and hemorrhaging and eventually kills the fish.

The court case was filed by Oceana which showed that Chile was using more antibiotics than any other fish and livestock producers in the world – 950 grams to raise one ton of fish. In contrast, Norway uses just 0.17 grams per ton of salmon.

Chile’s usage added up to 1.2 million pounds of antibiotics on two billion pounds of fish in 2014.

Since then, a retailer backlash against drug-drenched salmon has gained momentum.

In the U.S., Whole Foods only stocks farmed salmon from European countries, and Target has sold only wild Alaska salmon since 2010.

Costco, which used to buy nearly 10 percent of Chilean salmon exports to the U.S. – 600,000 pounds per week – now buys most of its farmed fish from Norway.

The Chilean marketing council said it plans to spend millions in its effort to win over wholesalers, retailers and food service companies with its new “Promise of Patagonia” campaign.

Meanwhile, U.S. salmon lovers can easily tell if the fish they are choosing is drug free.

Country of Origin Labeling laws since 2009 require fish to be identified as to where it comes from and if it is wild or farmed.