Bhubaneswar: Sale of fish and fish-based dishes in hotels and restaurants across the city have taken a hit after it emerged that formalin, a water solution of formaldehyde that can cause severe health problems, was present in them.

While marine fish species such as pomfret and hilsa have gone missing from menus, the situation is likely to worsen even though the director of fisheries, P. K. Senapati, on Wednesday advised consumers not to panic.

Sheikh Mustafa, an adviser to Jaya Jawan Maschhya Byabasai Sangha, an association of traders of wholesalers at Unit-IV market, said around two tonnes of marine fish used to be sold at the market a week. "The sale of marine fish has declined ever since the chemical was found in fish on Friday. As buyers are in panic, we decided to ban the sale of marine and preserved fish till July 25," he said.

Hotel owners admitted that their businesses had been taken a hit. "Earlier, we used to buy around 40kg of fish, including marine varieties, daily. That has declined to around 15kg. Most customers are reluctant to eat fish," said an employee of Durga Restaurant, famous for its fish dishes.

Archana Jena, manager of Odisha Hotel, a popular Odia cuisine restaurant, said most customers were reluctant to have fish on their menus. "Though only one sample tested positive, customers are reluctant to have fish items. The government should initiate steps to prevent the sale of the fish laced with chemicals to restore the faith of customers," she said.

Senapati, however, said fish samples collected from various sources and procured from inland fisheries returned negative results for formalin. "Surprise raids will continue in all districts and samples collected from traders, wholesalers and fish consignments coming from Andhra Pradesh for laboratory tests," he said.

On Friday, a 12-member team of the fisheries and animal resources development department collected samples from markets after the state government ordered tests after the Assam government banned fish import because of presence of the carcinogenic chemical. The samples included prawn, rohu, mirkali, crabs and pomfret. Out of eight samples, one sample of pomfret had tested positive for formalin.