Saltwater fish sales fell yesterday after samples were found to contain a cancer-causing antibiotic, but traders expect business to return to normal within days. Freshwater fish traders were also given hope that supplies from the mainland, suspended more than 10 days ago, could resume soon. Sales fell after the Centre for Food Safety said on Thursday it had found samples of pompano, flowery garoupa and tiger garoupa containing nitrofuran, a banned antibiotic. 'Sales of pompano have slumped nearly 50 per cent, while garoupa has dropped slightly by about 5 per cent,' Chamber of Seafood Merchants chairman Lee Choi-wah said. 'Generally, sales of saltwater fish have dropped by only about five to 10 per cent. Luckily, it is not that serious.' He believed that because the levels of nitrofuran found in the samples were low - between 0.0026 and 0.47 parts per million - the scare could ease within one or two days. A ParknShop spokeswoman said all of its 60 supermarkets that sold fish had temporarily halted sales of pompano after a tainted sample was found in its Tai Kok Tsui superstore. She said the pompano was supplied by a registered fish farm on the mainland, and said ParknShop was co-operating with the safety centre's investigation. Guangdong Governor Huang Huahua yesterday also offered hope for the freshwater fish industry, saying in Zhuhai that exports into Hong Kong, which were suspended after samples were found to be tainted with the cancer-causing chemical malachite green last month, would soon resume. But he did not say when. Tommy Hui Hon-man, of the Hong Kong, Kowloon and New Territories Freshwater Fish Wholesale Association, welcomed the news. 'More than 10,000 people working in related industries have been affected. Every one of us hopes the supply can resume as soon as possible,' he said.