When comparing omega-3 in fish, the most useful numbers are EPA and DHA, the long-chain omega-3 fats found in marine foods. They are not the same as ALA from flax, chia or walnuts.
Ranking per 3-ounce (85 g) serving
| Fish | EPA | DHA | EPA+DHA |
|---|---|---|---|
| Atlantic salmon, farmed, cooked | ~0.59 g | ~1.24 g | ~1.83 g |
| Atlantic herring, cooked | ~0.77 g | ~0.94 g | ~1.71 g |
| Sardines, canned, drained | ~0.45 g | ~0.74 g | ~1.19 g |
| Atlantic mackerel, cooked | ~0.43 g | ~0.59 g | ~1.02 g |
| Rainbow trout, wild, cooked | ~0.40 g | ~0.44 g | ~0.84 g |
| Light tuna, canned in water, drained | ~0.02 g | ~0.17 g | ~0.19 g |
These numbers come from one NIH table based on USDA food-composition data, making the serving sizes reasonably comparable. Species, origin and feed can still change the exact values.
Salmon does not always hold exactly the same rank
The farmed Atlantic salmon entry provides about 1.83 g EPA+DHA per 85 g, while wild Atlantic salmon in the same table provides roughly 1.57 g. That does not mean every farmed salmon is higher than every wild salmon; species and feed matter.
Sardines and mackerel are concentrated everyday sources
A serving of canned sardines supplies about 1.19 g EPA+DHA and Atlantic mackerel just over 1 g. Those amounts are roughly five to six times the ~0.19 g in a comparable serving of canned light tuna.
Fatty fish is not one fixed number
Fatty fish generally contains more EPA and DHA than lean fish such as cod or tilapia, but the spread is large. NIH lists cooked Pacific cod at only about 0.14 g EPA+DHA per 85 g, compared with more than 1 g in sardines, mackerel, herring or salmon.
Preparation matters
Canned values are usually reported for drained fish, while fresh fish values often use a cooked serving. Comparing 100 g raw with 100 g cooked can distort a ranking because cooking changes water content.
The practical takeaway
For EPA and DHA, salmon, herring, sardines and mackerel are especially dense choices. In comparable 85 g servings, each provides roughly 1–1.8 g EPA+DHA, far more than lean fish or canned light tuna.
EPA and DHA are the omega-3 forms that make fish distinctive
Fish rankings usually focus on EPA and DHA, the long-chain marine omega-3 fats. That is different from walnuts, flax, or chia, which provide mostly ALA. The body can convert some ALA to longer-chain forms, but conversion to EPA and especially DHA is limited.
For that reason, comparing only a generic “total omega-3” number can hide meaningful differences in which fatty acids are actually present.
Omega-3 content is only one part of choosing a fish
Species size, origin, farming or capture method, and environmental contamination can affect other considerations. Small oily fish such as sardines and herring often deliver substantial EPA and DHA while sitting relatively low on the food chain. For larger predatory species, consumption guidance may be influenced more strongly by mercury.
Rotating species gives nutritional variety and makes it easier to shop by season, price, and availability.
Canned, frozen, and fresh fish can all contribute
Freezing or canning does not erase the fish’s omega-3 content. Canned sardines, mackerel, or salmon can be practical choices; the main differences may be sodium, packing liquid, and added oil. Compare the drained serving rather than counting oil in the can as if it all came from the fish.
Cooking method matters more for the rest of the meal than for deciding whether the fish “still has omega-3.” Baking, gentle pan cooking, or stewing can keep preparation simple without adding large amounts of extra fat.
With canned fish, edible softened bones in sardines and some salmon can also raise calcium substantially when they are eaten. That benefit is separate from omega-3 and shows why two canned fish can have different mineral profiles even when EPA and DHA are similar. The specific label remains the best guide for sodium and serving size.
Portion frequency matters too. A fish that looks exceptional per 100 grams contributes little if it rarely appears on the menu, while a more accessible oily fish eaten regularly can make a larger contribution over time. Cost, taste, bones, convenience, and cooking skill all affect that real-world intake, so the “winner” on a nutrient table is not automatically the most useful choice for a household.
Sources
- NIH Office of Dietary Supplements — Omega-3 Fatty Acids — Comparison table of EPA and DHA in fish and seafood servings.
- USDA FoodData Central — Food-composition database underlying many NIH food references.