Police in the Fylde are warning of rogue fish sellers knocking at people's doors and trying to sell overpriced, low quality fish.
Police said they have had a number of reports of men visiting homes in Kirkham, Freckleton, Warton and Lytham.
A police spokesman said: "We have received a number of calls regarding men posing as fish sellers.
"In most cases, the quality of the fish is extremely poor and the type/amount of fish has been mis-sold.
"We wish to remind everyone to stay vigilant and please report any suspicious behaviour."
One woman in Freckleton Street, Kirkham, said she had been visited by two men trying to sell her fish at inflated prices.
"They were at our door trying to sell me fish and they wanted £295 for two bags of mixed fish packs", she said.
A number of people have described the men as having North-East and Scottish accents.
Trading Standards have advised people to take a number of precautions when answering the door to cold callers.
This is what you should do if they come knocking.
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What you should do if a cold caller knocks at your door
1. NEVER agree to have any work done as a result of a cold call. Do not make snap decisions and do not be pressurised into having the job done.
2. If you think work needs doing to your home, get quotes from 2 or 3 traders. Ask friends and relatives to recommend a reputable business.
3. Ask for the full name and address from a trader BEFORE considering dealing with them. Never rely solely on a mobile telephone number.
4. Ask for a written quotation detailing all the proposed work and a final price for the job.
5. Only pay once the work is completed to your satisfaction. Do not pay cash. Do not pay money up front for trader's materials.
6. Check the identity of all callers to your home. Ask for photo identification, even if the caller claims to be from a utility company, the police or local authority. Check it carefully with the telephone number in the phone book, NOT the number on the ID.
7. If in doubt, DO NOT open the door, report any suspicious callers to the Citizen's Advice consumer helpline (03454 04 05 06), or police on 101.