A skewband grunt sample has been found to have trace amounts of malachite green, the Agriculture, Fisheries & Conservation Department says.
The sample was taken from taken from a local fish farm, which is a participant in the Accredited Fish Farm Scheme.
It was among a batch of samples collected for testing during regular monitoring.
The batch has not entered the market, and the department is interviewing with the fish farmer to ascertain the source of malachite green.
The department will enhance monitoring of local fish farms while the Centre for Food Safety will enhance surveillance at retail level.
