Of the 12 samples of imported freshwater fish taken Monday, one was found to contain malachite green, the Agriculture, Fisheries & Conservation Department says.

Big head, grass carp and mud carp were sampled. It has notified the Mainland authorities of the test results.

The Government has so far tested 195 samples of 14 types of freshwater fish - 98 local and 97 imported. Malachite green has been detected in 19 samples, all imported. A freshwater grouper was found to contain the highest level of the hazardous substance.