Ordering fish at a restaurant should be simple, right? You scan the menu, pick something that sounds delicious, and trust that what arrives on your plate is fresh, safe, and exactly what you paid for. Reality, however, isn’t always that straightforward. The seafood industry is riddled with hidden pitfalls that most diners never even think about.
From mercury levels that could harm your health to fraudulent labeling schemes that trick you into paying premium prices for inferior fish, the choices you make at restaurants matter more than you might imagine. Let’s be real, the last thing you want is to unknowingly consume something that could pose risks to your well-being or support unsustainable fishing practices. So what fish should you actually avoid when dining out?
Swordfish: The Mercury Menace
Swordfish has a tendency to be high in mercury, making it a fish you should seriously think twice about ordering. Next to tilefish from the Gulf of Mexico, swordfish has the second highest level of mercury among fish and shellfish measured by the U.S. Food and Drug Administration, and along with tilefish, shark, and king mackerel, it is one of four types of fish the FDA advises pregnant women and young children to avoid. Mercury accumulates in large predatory fish over time as they consume smaller contaminated fish, and the health consequences can be serious.
Swordfish is often overfished, adding environmental concerns to the health risks. Though efforts like the Give Swordfish a Break Campaign helped replenish some stocks, sustainability remains an ongoing issue in certain regions. In some parts of the world, like the Central Mediterranean, swordfish are scarce. If you’re craving that firm, meaty texture, consider alternatives like mahi mahi or grouper instead.
Red Snapper: The Mislabeling King
Here’s the thing about red snapper: what you order is probably not what you’re actually getting. Researchers in this field have sometimes labeled red snapper as the number one fish species that gets mislabeled. The statistics are honestly shocking. One study from 2019 suggests red snapper mislabeling happened 77% of the time and that 100% of red snapper in sushi restaurants they studied was fake.
A 2025 study found that red snapper was mislabeled in more than 85% of samples, with the fish often switched out for tilapia. You might think you’re paying top dollar for premium red snapper, but restaurants and suppliers substitute it with cheaper alternatives like vermillion snapper or tilapia. Red snapper has been overfished in recent decades and is more rare, so sellers are looking to make extra money by selling something cheaper. It’s frustrating, really. You can’t trust what’s on the menu to match what lands on your plate.
Eel: A Toxic Gamble
Eel has been consumed by humans for thousands of years and remains popular fare across both Europe and Asia, where it is used to make everything from English jellied eels to Japanese unadon. Yet ordering eel at a seafood restaurant comes with substantial risks that most people don’t realize. Eel blood contains a toxin that can provoke muscle cramping, including critically, cramping of the heart muscle, in humans and other mammals.
When eel is cooked, this toxin is rendered harmless, but even a small amount of raw eel blood could kill you. According to the Food and Drug Administration, many species of eel can carry parasites and harmful toxins which cause food poisoning, and moray eels in particular may contain high levels of ciguatoxins that cause ciguatera food poisoning, with unpleasant side effects including nausea, vomiting, and blurred vision that can last for months. Overfishing has contributed to eel’s severe decline in many regions, though some regulations are now in place to try to aid recovery. Sustainability issues, food safety concerns, and toxicity risks make eel a fish best left off your plate.
Atlantic Cod: Sustainability Nightmare
Atlantic cod might seem like a safe, familiar choice, but it’s actually one fish you need to ask questions about before ordering. Cod stocks have suffered heavily from overfishing on both sides of the Atlantic, and in the major fishing areas for cod in US and Canadian waters of the Northwest Atlantic, stocks have been overfished and continue to be overfished, with all stocks classified as being overfished or at risk of being harvested unsustainably.
If a restaurant serves Atlantic cod, you should confirm it comes from sustainable sources. When it comes to Atlantic cod harvested from waters off the coast of the United States, you’ll want assurance that it’s pole-and-line caught in one of two specific locations: Georges Bank or the Gulf of Maine. Pacific cod is a worthy alternative that’s plentiful at the moment, but you’ll want assurance that it was caught in the United States or Canada, which are both countries with the safest fishing practices. Cod are often caught using bottom trawling gear which damages seabed habitats that are important for the survival of many other species, so sourcing matters tremendously.
Tuna (Especially Albacore): Mercury Central
Tuna is the most common source of mercury exposure in the country, which should make anyone pause before ordering that tuna steak or spicy tuna roll. Tuna samples contained the highest mercury concentrations, and tuna concentrations were highly dependent on their species and brand, with albacore tuna samples having the greatest mercury content. In fact, several albacore samples exceeded the FDA’s approved limit of 1 PPM.
All stocks of all species of tuna are fished at full capacity, and many are declining or depleted, with southern bluefin tuna, bigeye tuna, and northern bluefin tuna endangered. The problem extends beyond health concerns to environmental devastation. Tuna is mainly caught using purse seines or long-lines, methods associated with a high unintentional catch of other fish species. If you regularly eat canned tuna, stick to light or skipjack tuna and limit it to less than two servings a week, with children eating only about four ounces of light tuna per week, and children should avoid albacore tuna altogether while women of childbearing age should stick to no more than four ounces per week.
