Which Seafood Is Fatty? Your Guide to Healthy Omega-3s

November 29, 2025 •

4 min read

The American Heart Association recommends eating two servings of fatty fish per week to support cardiovascular health. Understanding which seafood is fatty is key to maximizing your intake of beneficial omega-3 fatty acids, which are crucial for optimal body and brain function.

Quick Summary

Several seafood varieties are rich in fat, particularly healthy omega-3 fatty acids, including cold-water fish like salmon, mackerel, and sardines, which offer significant heart and brain benefits.

Key Points

Rich in Omega-3s: Fatty seafood like salmon, mackerel, and sardines are excellent sources of heart-healthy omega-3 fatty acids EPA and DHA.
Supports Heart and Brain: Regular consumption of fatty fish is linked to improved cardiovascular health, better brain function, and reduced inflammation.
Differ from Lean Fish: Unlike lean fish (cod, tilapia), fatty fish store oil throughout their flesh, which affects cooking and flavor.
Manage Mercury Intake: Be aware of mercury levels in larger predatory fish like shark and swordfish, especially for pregnant women and young children.
Versatile and Budget-Friendly: Options like canned sardines and anchovies provide a convenient and affordable way to boost your omega-3 intake.

The Health Benefits of Fatty Seafood

Contrary to saturated fats found in some meat products, the fat in seafood is predominantly unsaturated, with a high concentration of beneficial omega-3 fatty acids, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). These nutrients are essential because our bodies cannot produce them in sufficient quantities, so they must be obtained through our diet. The health benefits associated with a diet rich in fatty fish are extensive and well-documented:

Heart Health: Omega-3s are known to help lower blood pressure, reduce triglyceride levels, and decrease the risk of irregular heartbeats and sudden cardiac events. Research consistently links regular fish consumption to a lower risk of cardiovascular disease.
Brain Function: DHA is particularly important for brain and eye development and function. Studies suggest that people who eat more fish may experience slower rates of age-related cognitive decline.
Mental Health: Research has shown that omega-3s may help alleviate symptoms of depression and can increase the effectiveness of antidepressant medications.
Reduced Inflammation: The anti-inflammatory properties of omega-3s may help manage and reduce the risk of inflammatory conditions, such as rheumatoid arthritis.
Vision Protection: Omega-3 fatty acids, especially DHA, may offer protection against age-related macular degeneration (AMD), a leading cause of vision impairment in older adults.

Popular Fatty Seafood Choices

Many different types of seafood fall into the fatty category. These are typically cold-water species that accumulate oil throughout their body tissues and belly cavity, as opposed to lean, white fish that store fat mainly in their liver. Here are some of the most common and beneficial options:

Salmon

Salmon is a standout for its high content of omega-3s, vitamin D, and B vitamins. There are nutritional differences between wild-caught and farmed salmon, though both are excellent sources of healthy fats. Farmed salmon may have a higher fat content due to their diet, while wild salmon's fat levels can vary seasonally.

Mackerel

Mackerel is a small, oily fish that is incredibly rich in omega-3s, as well as vitamin B12 and selenium. It has an intense flavor that pairs well with strong seasonings and can be grilled, baked, or smoked.

Sardines and Anchovies

Often sold canned, these small, oily fish are budget-friendly and packed with nutrients, including protein, calcium, and iron. They are a convenient way to add a boost of heart-healthy omega-3s to salads, sandwiches, and sauces.

Herring

Like sardines and mackerel, herring is a medium-sized oily fish that is often sold pickled, smoked, or canned. It's a great source of protein and beneficial fats, especially when baked or pan-fried.

Trout

Species like rainbow trout are another excellent source of healthy fats. The fat content can be influenced by whether the fish is wild-caught or farmed.

Oysters and Mussels

While often overlooked as fatty seafood, these shellfish are rich in omega-3s, zinc, and vitamin B12. They can be a great way to diversify your seafood intake. Oysters are particularly noted for their high zinc content.

Fatty vs. Lean Fish: A Comparison

To highlight the distinction, here is a comparison of typical fatty fish versus lean fish varieties.


Feature	Fatty Fish (e.g., Salmon, Mackerel)	Lean Fish (e.g., Cod, Tilapia)
Fat Content	Higher fat levels (5-20%) distributed throughout the flesh.	Lower fat levels (<5%) concentrated primarily in the liver.
Omega-3s	Significantly higher content of heart-healthy EPA and DHA.	Lower content of omega-3s.
Flesh Color	Tends to have a darker or more colored flesh, like pink or orange.	Typically has a whiter or lighter flesh.
Cooking Method	Fats are released during cooking, making them suitable for grilling, baking, or broiling.	Prone to drying out; best cooked with moisture via steaming, poaching, or pan-frying with oil.

Risks and Considerations with Fatty Seafood

While the health benefits are clear, it's also important to be mindful of potential contaminants. Larger, longer-living predatory fish can accumulate higher levels of mercury and other pollutants. To minimize risk, regulatory bodies provide guidelines:

High-Mercury Fish: Species like shark, swordfish, king mackerel, marlin, and bigeye tuna should be consumed rarely, if at all.
Vulnerable Populations: Pregnant women, nursing mothers, and young children should be especially careful to avoid high-mercury fish and limit overall seafood intake to recommended levels.
Sustainability: Consider the environmental impact of your choices. Some resources, such as the Monterey Bay Aquarium's Seafood Watch, can help you choose more sustainable options.

Conclusion

For those seeking to add healthy fats to their diet, the answer to which seafood is fatty is clear: look to species like salmon, mackerel, sardines, and herring. These omega-3 rich fish offer substantial benefits for heart, brain, and overall health, especially when replacing other sources of saturated fat. By being aware of different species' fat profiles and making informed choices about mercury content and sustainability, you can easily incorporate delicious and highly nutritious fatty seafood into your regular meals. For detailed nutritional information on specific fish, consulting reliable sources like the National Institutes of Health is recommended.

NIH Office of Dietary Supplements: Omega-3 Fatty Acids Fact Sheet

Frequently Asked Questions

The main difference lies in where the fish stores fat. Fatty fish, such as salmon and mackerel, store oil throughout their body tissues, giving them a higher fat content. Lean fish, like cod and tilapia, store fat primarily in their liver, resulting in much leaner flesh.

The fats in seafood, particularly in fatty fish, are primarily omega-3 fatty acids (EPA and DHA), which are unsaturated and offer significant health benefits. They help reduce inflammation and support heart and brain health, unlike the saturated fats found in some other animal products.

Many fatty fish are great for heart health due to their high omega-3 content. Excellent options include salmon, mackerel, herring, and sardines. The American Heart Association specifically recommends eating these types of fish twice a week.

Yes, canned fatty fish like sardines are a very healthy and affordable option. They retain their high omega-3 content and are also rich in other nutrients like calcium, protein, and vitamin D, especially when consumed with the bones.

It depends on the type and preparation. Bluefin and albacore tuna can be considered oily fish, rich in omega-3s, while light canned tuna is leaner. However, due to mercury concerns, some types of tuna should be consumed in moderation, especially by vulnerable groups.

Larger predatory fish such as shark, swordfish, king mackerel, marlin, and tilefish tend to have higher mercury levels. These should be eaten in limited amounts or avoided, particularly by pregnant women, nursing mothers, and young children.

A standard serving size is typically 3 to 4 ounces of cooked fish, which is about the size of a deck of cards. The American Heart Association recommends two such servings of fatty fish per week.