FOOD

The most ‘poisonous’ fish in the world: it has 70 parasites and is eaten in practically every home

Rich in Omega-3, protein and vitamins B and D, it is one of the most consumed fish in the world, but a new health study questions its safety.

Luis Méndez Calum Roche

Update: May 9th, 2025 16:58 EDT

Salmon is one of the most popular fish worldwide – but it naturally contains more than 70 parasites. And in the pens where they are farmed, the fish are often exposed to chemicals that can pose health risks to consumers.

The reason salmon hosts so many parasites is tied to its life cycle: when young, these fish tend to stay near coastal areas, where they come into close contact with marine mammals that perpetuate the parasite life cycle.

Angler in Norway showing sea lice damage to a wild Atlantic salmon in the salmon farming zone.

Nearly all farmed salmon have rotten fins like this. It’s not clear if it’s by lice or a bacterial condition, perhaps brought on by stress. But it is a sign of systemic poor welfare. pic.twitter.com/GLcJuPzNuA
— Salmon Scotland (@SalmonScotland) October 6, 2024

Conditions in fish farms

Beyond what bugs the salmon itself carries, the conditions in which it’s raised in aquaculture systems may be just as concerning. Farmed salmon are fed a processed diet made from fish meal and various chemical additives. To prevent disease, caretakers frequently use pesticides and antibiotics – many of which end up on the fish’s surface and, ultimately, in the human body.

Workers at these facilities often wear protective suits and gear because toxic substances are used to maintain sanitary conditions in the pools. Ironically, though these chemicals are meant to protect the fish, they can still carry health risks for the people who consume them.

Ensuring the responsible and prudent use of #antimicrobials in fish farming and aquaculture is a major challenge. Over the past 30 years #Norway has successfully applied scientific innovation and implemented key legislation to achieve this objective in salmon production. pic.twitter.com/wtsF2s52xI
— World Organisation for Animal Health (@WOAH) August 31, 2024

Wild vs farmed salmon

It’s important to distinguish between wild and farmed salmon. Wild salmon feed naturally and have a more balanced nutritional profile, while farmed salmon typically contain more harmful fats and toxic contaminants.

From a calorie standpoint, there’s a big difference too: the salmon most commonly found in homes – usually farm-raised – contains around 212 calories per 100 grams, compared to just 115 calories in the same amount of wild salmon.

Despite these concerns, many people continue to eat salmon due to its high Omega-3 content. Some experts suggest turning to alternative fish like sardines, which are also rich in Omega-3s but may carry fewer risks.

The benefits of eating salmon

While concerns around farming practices and contaminants are real, salmon also offers several well-documented health benefits:

Excellent source of protein and minerals, including iodine, magnesium, phosphorus, selenium, iron, and calcium
Rich in vitamins that support thyroid and gut function
High in vitamin D, which is key for bone development and strength
Contains properties that may combat certain skin issues and help prevent skin cancer
Offers anti-inflammatory benefits, helping slow the skin’s aging process

How will Trump’s tariffs affect the salmon business?

President Donald Trump’s renewed push for reciprocal tariffs is casting uncertainty over the U.S. seafood industry, particularly for salmon imports and exports. The U.S. relies heavily on imported seafood - Canada alone accounts for over 90% of U.S. salmon imports - while also exporting large volumes of wild-caught salmon to countries like China. Both nations have already indicated retaliatory responses to Trump’s latest tariff proposals. These moves threaten to disrupt critical trade flows and drive up costs for U.S. seafood businesses and consumers alike.

Trump’s stance also risks undercutting support from fishing communities that have traditionally backed him due to his deregulatory agenda and opposition to offshore wind farms. In Alaska, where Trump won by a wide margin, the salmon industry is especially vulnerable – China is its top export destination, and much of the fish is processed in China before returning to the U.S. for sale. Industry leaders and lawmakers have raised concerns that tariffs could not only shrink export markets but also increase operational costs, including equipment and labor, while compounding pressures from climate change and cuts to federal support agencies like NOAA.