The glistening ice, clean white trays, and colorful filets behind your grocery store seafood counter are designed to look pristine and trustworthy. But beneath the surface of that clean presentation, there’s a world of deception, questionable sourcing, and unsafe practices that would make most shoppers think twice.
Seafood is one of the most complex and poorly regulated categories in the global food supply, and unfortunately, your local supermarket is often ground zero for many of the industry’s worst habits.
From fake fish to chemical treatments and seafood with a passport longer than yours, here are nine alarming truths hiding in plain sight behind the seafood counter and what you need to know to protect your wallet, your health, and your conscience.
1. You Might Not Be Buying the Fish You Think You Are
Seafood fraud is rampant. According to a study by Oceana, 1 in 5 seafood samples globally is mislabeled, with cheaper or lower-quality fish substituted for more expensive ones. At your supermarket, that “wild-caught red snapper” might actually be tilapia or rockfish. Or that pricey “sea bass” could be an entirely different species with no resemblance in flavor or nutrition.
Why does this happen? Because once a fish is filleted and skinned, even trained eyes have trouble telling them apart. Unscrupulous suppliers and middlemen take advantage of this to pass off low-cost fish under premium names, especially in frozen, pre-packaged, or bulk offerings.
2. “Fresh” Fish Is Often Previously Frozen
If a seafood label says “fresh,” you probably picture a recent catch. But in many cases, that fish was frozen at sea, then thawed for display just before it hit the seafood counter. There’s nothing inherently wrong with freezing fish—it can preserve nutrients and texture quite well. The problem is when supermarkets don’t disclose it and charge premium prices for a product that’s already been defrosted days (or even weeks) before.
Look for phrases like “previously frozen,” “refreshed,” or “may have been frozen for transport” on fine print near the price tag, or ask your fishmonger directly. If they hesitate or don’t know, consider that a red flag. You may be overpaying for a defrosted product with a shorter shelf life and unknowingly bringing home fish that’s already on the clock.
3. Imported Fish Often Comes From Questionable Farms
About 90% of the seafood sold in U.S. grocery stores is imported, and a large portion of that comes from fish farms in countries with little to no environmental or safety oversight. In parts of Southeast Asia, for instance, farmed shrimp and tilapia are often raised in polluted waters and crowded conditions and fed with antibiotics, hormones, and even animal feces. These contaminated environments have been linked to antibiotic-resistant bacteria and dangerous pathogens.
Because of lax regulations, these fish can pass through global supply chains and land on your dinner plate without you ever knowing the true conditions of their origin. Imported fish might carry more than flavor. It could come with antibiotics, heavy metals, and unsafe bacteria that U.S. food laws would never allow.
4. Carbon Monoxide Is Used to “Freshen” Fish Color
That beautiful, vibrant red tuna steak at your local supermarket? It might owe its bright hue not to freshness but to carbon monoxide gas. This gas is sometimes used in packaging tuna and other fish to lock in color, making old fish look fresher than it actually is. It doesn’t preserve taste or safety, just appearance. In fact, fish treated this way may smell fine but be dangerously spoiled inside.
While legal in the U.S. with proper labeling, many grocers fail to disclose carbon monoxide use or rely on distributors who use it before shipment.
5. Glazing and Weight Padding Are Common Pricing Tricks
Glazing is the process of coating frozen fish in ice to prevent freezer burn. It’s normal up to a point, but in many grocery chains, over-glazing is used to inflate weight and pad profit margins. In some cases, up to 30% of the fish’s total weight is just ice. That means when you pay by the pound, a good chunk of your money is literally going down the drain as soon as you thaw it. Some stores even pump water or sodium-based solutions into filets to boost weight and give fish a falsely tender texture, further distorting value and nutrition.
6. Many Fish Are High in Mercury and Heavy Metals
Certain fish, especially larger predatory species like tuna, swordfish, shark, and king mackerel, contain dangerously high levels of mercury—a neurotoxin that accumulates over time and can impact brain function, especially in children and pregnant women. Even smaller species like Chilean sea bass or grouper can carry high levels of PCBs (polychlorinated biphenyls) and arsenic, depending on their region of origin.
Yet many supermarkets fail to post mercury warning signs or educate customers about safer alternatives—leaving consumers to unknowingly feed their families potentially hazardous meals.
7. Sustainable Options Are Rarely Labeled Clearly
While many shoppers try to make eco-conscious choices, grocery store seafood counters often make that difficult. Terms like “wild-caught” and “farm-raised” don’t tell the full story, and most stores fail to indicate which fish are responsibly sourced or certified by groups like the Marine Stewardship Council (MSC) or Aquaculture Stewardship Council (ASC).
Sustainable seafood sourcing is complex and varies widely by species and region. Yet few seafood counters provide details about fishing methods, bycatch risks, or environmental impact, forcing shoppers to rely on vague marketing rather than facts. Without proper labeling, even well-intentioned consumers may end up supporting destructive fishing practices and unsustainable farms.
8. Parasites and Bacteria Are More Common Than You Think
Unlike beef or poultry, seafood is often consumed raw or lightly cooked—think sushi, ceviche, or seared tuna. However, what most consumers don’t realize is that raw seafood from supermarkets carries a high risk of parasites and pathogens.
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Anisakis worms in undercooked wild salmon
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Listeria and Vibrio bacteria in oysters and shellfish
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Hepatitis A outbreaks linked to imported scallops or clams
While reputable sushi restaurants freeze their fish to kill parasites, most supermarket seafood does not meet the same standards, making raw consumption far riskier. Unless you’re 100% sure of its sourcing and handling, supermarket seafood should always be fully cooked to avoid serious illness.
9. Some “Wild-Caught” Labels Are Flat-Out False
Consumers often seek out “wild-caught” fish, believing it’s healthier, more sustainable, or better tasting. But just like “organic” or “natural,” the term “wild-caught” is frequently misused—or outright fabricated. A 2019 NOAA investigation found multiple instances of farm-raised fish being sold as wild-caught, especially in species like salmon, catfish, and even crab. Without consistent third-party verification, it’s incredibly difficult to confirm a fish’s true origin just by looking at the label.
Even more troubling: the average grocery store employee may have no idea where the fish came from or what’s behind the brand name printed on the sticker.
So What Can You Do? Smarter Seafood Shopping Starts Here
While all of this may sound discouraging, it doesn’t mean you have to swear off seafood completely. Here are a few practical tips to shop smarter and protect your health:
- Ask Questions – Talk to the seafood counter attendant. Ask where the fish came from, whether it was previously frozen, and whether it’s been treated with carbon monoxide or additives.
- Check for Certification Labels – Look for labels from MSC, ASC, or Best Aquaculture Practices (BAP). These indicate stronger standards in sustainability and safety.
- Buy from Reputable Fishmongers or Specialty Market – If possible, shop from local markets that specialize in seafood. They often have better sourcing transparency and fresher products.
- Use Online Seafood Guide – Resources like the Monterey Bay Aquarium’s Seafood Watch app can help you identify safe, sustainable choices at the grocery store.
- When in Doubt, Cook Thoroughly – Avoid eating raw supermarket seafood unless it’s labeled “sushi-grade,” and you’re confident in the store’s handling practices.
Know What You’re Really Bringing Home
The seafood counter might look like a clean, safe haven of fresh ocean flavor, but as we’ve seen, it often hides layers of murky practices. From mislabeling and chemical tricks to contamination and sustainability concerns, your grocery store fish could be a far cry from what you think you’re buying.
The good news? Awareness is power. Armed with the right questions and a critical eye, you can still enjoy delicious seafood without the hidden dangers or hidden fees.
Have you ever discovered something sketchy at the seafood counter or had a fishy buying experience that made you swear off supermarket seafood?
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Riley is an Arizona native with over nine years of writing experience. From personal finance to travel to digital marketing to pop culture, she’s written about everything under the sun. When she’s not writing, she’s spending her time outside, reading, or cuddling with her two corgis.