Less than a quarter of the price, sold at nearly the same cost.
In the storied tradition of the British fish and chip shop — a cultural institution as much as a meal — a quiet substitution has been taking place. A BBC investigation found that three of ten tested establishments in Liverpool and Manchester were serving Southeast Asian catfish to customers who believed they were eating cod or haddock, exploiting a vast price gap and a legal framework that requires disclosure only when a customer thinks to ask. The deception is not one of danger but of trust: people were paying for heritage and receiving something else entirely, unaware that the batter concealed a different story.
- DNA barcoding at Liverpool John Moores University confirmed that three of ten sampled shops were selling pangasius catfish — farmed in Southeast Asia at roughly £3.40 per kilogram — while charging customers prices consistent with cod or haddock at nearly five times the wholesale cost.
- Customer reviews had already sounded the alarm, with diners writing that the fish tasted wrong and that they genuinely could not identify what species they had eaten — a confusion that pointed investigators toward these specific establishments.
- The fraud is structurally difficult to catch: once a fillet is battered and fried, even trained eyes struggle to distinguish catfish from traditional white fish, and the DNA testing needed to prove misrepresentation is too costly for routine regulatory use.
- UK law creates a quiet loophole — species disclosure is only required if a customer explicitly asks, meaning shops can hide behind vague menu language like 'traditional fish and chips' without technically breaking the rules until pressed.
- Researchers described a three-in-ten substitution rate as unusually high, raising questions about how widespread the practice may be beyond the ten shops tested and whether enforcement mechanisms are adequate to protect consumers.
A BBC investigation has uncovered a quiet deception running through some English fish and chip shops: catfish from Southeast Asia being served in place of the cod and haddock customers believe they are ordering. The trail began with online reviews — diners expressing genuine confusion about what species they had eaten, some noting the fish tasted nothing like proper cod. Those comments led researchers to ten establishments in Liverpool and Manchester, which became the focus of DNA testing.
Seven of the shops listed cod or haddock on their menus. The other three offered only vague descriptions — 'normal fish' or 'white fish' — and when questioned, staff pointed to signs advertising 'traditional fish and chips.' DNA barcoding at Liverpool John Moores University confirmed that three of the ten were selling pangasius, a farmed catfish imported from Southeast Asia. The economics explain the temptation clearly: catfish costs around £3.40 per kilogram wholesale, against roughly £15 for cod or haddock. Customers were paying between £3.80 and £5 per portion and receiving a product that cost a fraction of what they thought they were getting.
Professor Stefano Mariani, who oversaw the testing, called a three-in-ten rate unusually high. The substitution is effective precisely because battered and fried fillets are nearly impossible to distinguish by sight or taste without specialist knowledge. The deeper problem, however, is structural: fish fraud cases are typically caught through intelligence-led investigations rather than routine monitoring, and the DNA testing required to prove deception is expensive. UK law compounds the issue by requiring species disclosure only when a customer asks — meaning vague menu language offers legal cover until someone thinks to question it.
Catfish is safe to eat and widely consumed around the world. The concern here is not health but honesty — customers ordering a dish with a specific cultural identity and flavor were receiving something else without being told, and the systems meant to prevent that are struggling to keep pace.
A BBC investigation has revealed that some fish and chip shops across England are quietly substituting catfish for the traditional cod and haddock their customers expect, pocketing the difference in cost without being transparent about the swap.
The discovery emerged after researchers analyzed dozens of online customer reviews in which diners expressed confusion about what they had actually been served. Many wrote that they had no idea which species of fish was on their plate; others specifically noted the fish tasted nothing like proper cod or haddock, suspecting instead they had been given something cheaper. These comments pointed the BBC toward ten establishments—five in Liverpool, five in Manchester—that became the focus of DNA testing.
When the BBC approached these shops, the picture became clearer. Seven of them listed either cod or haddock on their menus. The remaining three offered only vague descriptions: "normal fish" or "white fish." Under UK law, businesses must disclose the species if a customer asks, but there is no requirement to volunteer the information upfront. When questioned, staff at the three shops with unlabeled offerings pointed to signs advertising "traditional fish and chips"—a claim that turned out to be misleading.
DNA barcoding performed at Liverpool John Moores University confirmed what the BBC suspected: three of the ten shops had been selling pangasius, a type of catfish farmed and imported from Southeast Asia. The economics of the deception are stark. Catfish costs roughly £3.40 per kilogram at wholesale prices, compared to £15 per kilogram for cod or haddock—less than a quarter the price. The three shops selling catfish charged between £3.80 and £5 per portion, while genuine cod or haddock typically went for £4 to £6. Customers were paying for premium fish and receiving a budget alternative, often without knowing the difference.
Professor Stefano Mariani, who oversaw the testing with researcher Catherine Perfect, noted that finding catfish in three out of ten sampled shops represented an unusually high rate. "In my experience with fish and chips, three out of 10 is quite a lot," he said. The substitution works partly because catfish fillets are difficult to distinguish from traditional white fish once they are battered and fried. Mariani emphasized that without formal training in fish biology, an ordinary customer would struggle to tell one fillet from another on sight or taste alone.
The investigation has exposed a gap in food safety enforcement. Cases of fish misrepresentation are typically uncovered through intelligence-led investigations rather than routine monitoring, and the DNA testing required to prove fraud is expensive and time-consuming. This makes widespread policing of the practice impractical for regulators. Catfish is safe to eat and is widely consumed in many parts of the world, but the issue here is not safety—it is honesty. Customers ordering fish and chips are paying for a specific product with a specific heritage and flavor profile. When they receive something else without being told, they have been deceived, regardless of whether what they ate was nutritionally sound.
Citações Notáveis
In my experience with fish and chips, three out of 10 is quite a lot—I don't recall seeing this level of catfish.— Professor Stefano Mariani, Liverpool John Moores University
It is very hard for a member of the public who is not a trained fish biologist to identify one fillet from another.— Professor Stefano Mariani
A Conversa do Hearth Outra perspectiva sobre a história
Why would a shop take this risk? The price difference can't be worth getting caught.
The margin is substantial—they're buying catfish at a quarter the cost of cod but selling it at nearly the same price. For a busy shop moving dozens of portions a day, that adds up quickly. And the risk feels manageable because enforcement is weak.
How would a customer even know they've been cheated?
They wouldn't, most of the time. The BBC only found these shops because people left confused reviews online. Once it's battered and fried, catfish looks and tastes similar enough that most people can't tell. That's what makes it such an effective fraud.
Is catfish actually bad for you?
No, it's perfectly safe. That's almost what makes this worse—it's not a health scandal. It's a straightforward lie about what you're paying for. You ordered cod; you got something cheaper. The shop kept the difference.
What stops this from happening everywhere?
Mostly luck and the cost of testing. DNA barcoding works, but it's expensive and slow. Regulators can't test every shop routinely. They rely on tips and complaints, which means most fraud probably goes undetected.
So what happens now?
That depends on enforcement. The law requires shops to tell you the species if you ask, but it doesn't require them to advertise it honestly upfront. That's the loophole these shops exploited.