14 Fish You Should Consider Never Eating

Fish are widely praised as one of the healthiest sources of protein, loaded with essential nutrients like vitamin D, selenium, and high-quality omega-3 fatty acids, which are known to support brain and heart health. However, despite their many benefits, not all fish are created equal — some should be eaten sparingly or avoided entirely due to concerns about mercury contamination, environmental impact, and farming practices.

Mercury is a heavy metal that accumulates in the bodies of large, predatory fish over time. When humans consume too much mercury, it can cause serious health issues, particularly affecting the nervous system and brain. This is especially risky for pregnant women and young children, as mercury exposure can harm fetal and early childhood development.

Among the fish to watch out for are shark, swordfish, king mackerel, and tilefish, which are known for their high mercury content. Bluefin tuna, while prized in sushi, is not only high in mercury but also overfished, pushing this magnificent species closer to extinction. Similarly, orange roughy is another example of a fish that accumulates mercury and has a long lifespan, making it both a health and environmental concern.

Caviar, often considered a luxury delicacy, is produced from sturgeon — a species that has become critically endangered due to overfishing and habitat loss. By purchasing caviar, consumers may inadvertently support harmful practices that threaten the survival of these ancient fish.

Farmed fish present a different set of challenges. Imported catfish, farmed shrimp, and tilapia are frequently raised in crowded, unsanitary conditions and treated with antibiotics and chemicals to combat disease and parasites. These practices can lead to contamination with harmful bacteria and residues that may pose risks to human health. Furthermore, tilapia contains relatively low levels of heart-healthy omega-3s and is higher in inflammatory omega-6 fatty acids, making it a less desirable choice nutritionally.

Atlantic cod, halibut, flounder, and sole are other examples of species that are under immense fishing pressure. Decades of overfishing have severely depleted their populations, leading to ecosystem imbalances and threatening future availability. Chilean sea bass (also known as Patagonian toothfish) and eel are similarly problematic, as they are both at risk from unsustainable fishing practices and are known to contain elevated levels of mercury.

When choosing seafood, it’s crucial to look for options that are both healthier and more sustainable. Wild-caught Alaskan salmon is a standout choice — it is rich in beneficial omega-3 fatty acids and sourced from well-managed fisheries that prioritize environmental health. Pacific sardines are another excellent option; they are small, low on the food chain, and reproduce quickly, making them both low in mercury and sustainable. Atlantic mackerel also offers a great balance of high omega-3 content and relatively low mercury levels, while being abundant enough to support responsible harvesting.

Consumers who want to make the most informed choices can refer to reputable resources like the Environmental Defense Fund’s Seafood Selector or the Monterey Bay Aquarium’s Seafood Watch guide. These tools provide up-to-date information on the health and environmental impact of various seafood options, helping individuals make decisions that support both their well-being and the health of our oceans.

Ultimately, by avoiding high-mercury, overfished, and poorly farmed species and choosing sustainable, nutrient-rich fish, we can enjoy the benefits of seafood while protecting our health and the future of marine ecosystems. Making conscious, informed decisions at the seafood counter is a powerful way to promote a healthier planet and a healthier you.