What Seafood is High in Omega-6?

November 20, 2025 •

4 min read

According to a 2017 study, some farmed seafood species, like Atlantic salmon, can have significantly higher omega-6 levels than their wild-caught counterparts. The answer to what seafood is high in omega-6 often lies in farming practices, which can dramatically alter the nutritional profile of fish and shellfish.

Quick Summary

Certain farmed seafood and processed products, like canned fish in oil, contain higher levels of omega-6 fatty acids due to diet and preservation methods. This influences the critical omega-6 to omega-3 ratio, which is important for managing inflammation. While these foods are still nutritious, a high intake can unbalance the body's fatty acid profile, emphasizing the need for balance.

Key Points

Farmed vs. Wild: Farmed fish, such as Atlantic salmon, channel catfish, and striped bass, typically have higher omega-6 levels due to being fed grain- and vegetable-oil-based diets.
Processed Products: Canned seafood packed in oil, including sardines and tuna, contains significantly more omega-6 than those packed in water, due to the vegetable oils used.
Cooking Method Impact: Frying any seafood can substantially increase its omega-6 content, as cooking oils rich in omega-6 are absorbed during the process.
Omega-6 to Omega-3 Ratio: A healthy balance of omega-6 to omega-3 is crucial for managing inflammation; a high intake of omega-6 from processed foods and farmed fish can worsen the imbalance common in Western diets.
Make Informed Choices: To ensure a healthier fatty acid profile, choose wild-caught fish, opt for water-packed canned options, and prepare seafood by baking, broiling, or steaming instead of frying.

Understanding Omega-6 in Seafood

Omega-6 fatty acids are essential polyunsaturated fats that the human body needs but cannot produce on its own. While typically associated with vegetable oils, nuts, and seeds, omega-6 fatty acids can also be found in seafood. The concentration in seafood, however, is heavily influenced by a critical factor: whether the seafood is wild-caught or farm-raised. Historically, marine fish have provided a balanced fatty acid profile, but changes in aquaculture feed have altered this.

The primary reason some seafood has elevated omega-6 levels is the shift towards plant-based feeds in commercial aquaculture. As fish oil has become more expensive, many fish farms have supplemented or replaced it with vegetable oils rich in omega-6, such as corn and soybean oil. This practice directly impacts the fatty acid composition of the fish that consume it, leading to a higher omega-6 to omega-3 ratio.

Farmed Fish with High Omega-6 Content

Several farmed species have been identified as having higher omega-6 content compared to their wild counterparts. The difference is a direct result of their grain-based diets in a controlled environment.

Farmed Atlantic Salmon: Studies have consistently found that farmed Atlantic salmon contains more total fat, including higher omega-6 levels, than wild salmon. The omega-6 to omega-3 ratio is therefore less favorable in the farmed variety, despite having high omega-3s overall.
Channel Catfish: Farmed channel catfish is another species known for higher omega-6 content due to its feeding habits in aquaculture.
Green Sturgeon, White Sturgeon, and Striped Bass: Researchers have found these farmed fish species contain significantly higher omega-6 concentrations compared to their wild kin.

Processed and Canned Seafood

Beyond farmed varieties, how seafood is processed and prepared can also increase its omega-6 content. This is largely due to the cooking oils used.

Canned Sardines in Oil: Some canned sardines are packed in vegetable oils, which dramatically increases their omega-6 concentration. For example, canned sardines in oil can contain thousands of milligrams of omega-6, whereas those canned in water have much lower levels.
Canned Tuna in Oil: Similar to sardines, canned tuna preserved in vegetable oil will have a much higher omega-6 content than tuna canned in water. A study showed canned tuna in oil with a very high omega-6 to omega-3 ratio.
Breaded and Fried Seafood: The practice of breading and frying fish or shellfish often involves vegetable oils rich in omega-6. Frying causes the seafood to absorb this oil, substantially increasing both the total fat and the omega-6 content.

The Importance of the Omega-6 to Omega-3 Ratio

While omega-6 fatty acids are essential, the ratio of omega-6 to omega-3 in the diet is a critical factor for overall health. A typical Western diet often has an imbalance, with ratios as high as 15:1 or 20:1, far exceeding the recommended 1:1 to 4:1 range. A high omega-6 to omega-3 ratio can promote inflammation, which is linked to various chronic diseases. Therefore, consuming seafood with a balanced ratio is generally considered more beneficial.

Balancing Your Intake

To maintain a healthier omega-6 to omega-3 ratio, consider these strategies:

Choose Wild-Caught Over Farmed: Opting for wild-caught fish, where available, can help ensure a lower omega-6 and more favorable fatty acid profile.
Select Water-Packed Canned Seafood: When buying canned fish like tuna or sardines, choose varieties packed in water rather than vegetable oil.
Use Healthier Cooking Methods: Instead of frying seafood, which adds omega-6 from cooking oils, choose healthier preparation methods like baking, broiling, steaming, or poaching.
Incorporate Other Omega-3 Sources: Increase your intake of omega-3s from other sources to help balance the ratio. This includes marine sources like algae oil and plant-based sources like flaxseeds, chia seeds, and walnuts.

Comparison: Omega-6 in Different Seafood Types


Seafood Type	Rearing Method	Primary Fat Type	Omega-6 to Omega-3 Ratio	Impact of Preparation
Wild Atlantic Salmon	Wild-caught	Omega-3 dominant	Low and balanced	Generally low impact; can increase with frying
Farmed Atlantic Salmon	Aquaculture	Higher total fat	Less favorable (Higher ω-6)	Higher omega-6 levels from feed; increases further with frying
Sardines in Water	Wild-caught	Omega-3 dominant	Low and balanced	Lower omega-6, maintains healthy profile
Sardines in Oil	Wild-caught	Omega-6 dominant	Unbalanced (Higher ω-6)	Soaking in vegetable oil drastically raises omega-6
Farmed Channel Catfish	Aquaculture	Higher omega-6	Less favorable	Higher omega-6 from feed; increases with frying
Wild Channel Catfish	Wild-caught	Balanced	Balanced	Natural fatty acid profile; can be altered by frying
Tuna in Water	Wild-caught	Lean; Omega-3 present	Low and balanced	Maintains lean profile
Tuna in Oil	Wild-caught	Omega-6 dominant	Unbalanced (Higher ω-6)	Oil used for canning dramatically increases omega-6

Conclusion

While many people associate seafood solely with beneficial omega-3s, certain types, particularly farmed varieties fed grain-based diets and fish canned in vegetable oil, can be significant sources of omega-6 fatty acids. Maintaining a healthy ratio of omega-6 to omega-3 is vital for managing inflammation and promoting cardiovascular health. By understanding the factors that influence the fatty acid content of seafood, consumers can make informed choices to ensure their diet is both healthy and balanced. Prioritizing wild-caught options and being mindful of how seafood is prepared and preserved can help you achieve a more beneficial fatty acid profile.

Frequently Asked Questions

No, not all seafood is high in omega-6. While some, particularly farmed and processed varieties, contain higher levels, wild-caught marine fish are generally recognized for having a more favorable, omega-3-dominant fatty acid profile.

Farmed fish often have higher omega-6 content because aquaculture feed has shifted from relying solely on fish oil to using more plant-based ingredients, such as corn and soy, which are rich in omega-6 fatty acids.

Not necessarily, as omega-6 is an essential fatty acid. However, a disproportionately high intake relative to omega-3 can lead to an unbalanced fatty acid ratio, which may increase inflammation in the body.

To get a better balance, opt for wild-caught seafood and select canned varieties packed in water instead of oil. When cooking at home, choose methods like baking, broiling, or steaming over frying.

While there is some variation in recommendations, many experts suggest aiming for a ratio between 1:1 and 4:1. This is significantly lower than the typical Western diet, which can be as high as 15:1.

Yes, but in much lower amounts than seafood canned in vegetable oil. The oil used for packing is the main contributor to the high omega-6 content in those products.

A chronically high ratio is linked to increased inflammation, which is a risk factor for various chronic diseases, including cardiovascular issues. However, the overall health impact depends on the context of your entire diet.