As the chlorine trucks rolled in on Tuesday morning, the last remaining prawn farm on the Logan River south of Brisbane was lost for the better part of the year.

Rocky Point Prawn Farm owner Serena Zipf said the federal government had failed south-east Queensland farms and it was now too late to salvage anything from the area.

The positive test results for the highly contagious white spot disease came back on Monday, shattering Ms Zipf and her close workers.

It was the seventh and final Logan River farm to become contaminated, after the sixth fell on February 6.