Tuna sits in a gray zone. Some species, like bluefin, are genuinely fatty fish with oil distributed throughout their flesh. Others, like skipjack (the most common canned tuna), are lean enough that major health organizations don’t classify them as oily fish at all. So the answer depends entirely on which tuna you’re eating.
Why Tuna’s Classification Depends on Species
Oily or “fatty” fish store fat throughout their muscle tissue, which is what gives salmon and sardines their rich flavor and high omega-3 content. Lean or “white” fish store most of their fat in the liver, leaving the flesh relatively low in oil. The British Heart Foundation specifically notes that fresh and canned tuna are not considered oily fish because they’re lower in overall fat, placing them alongside sea bass rather than salmon.
But that’s a generalization driven by the tuna most people actually buy. The American Heart Association lists bluefin tuna alongside salmon, mackerel, and sardines as a fatty fish high in omega-3s. Bluefin belly cuts used in sushi can contain 30 to 50% fat, rivaling some of the fattiest fish on the planet. The premium belly cut known as otoro is prized specifically for its creamy, melt-in-your-mouth fat content. Meanwhile, a can of light tuna packed in water contains less than 1 gram of total fat per 3.5-ounce serving.
Omega-3 Content Across Tuna Types
Even if a particular tuna isn’t classified as “fatty,” it still provides some omega-3s. The practical question is how much. In a 3.5-ounce serving:
- Canned albacore (white) tuna in water: 862 mg of EPA and DHA combined
- Canned light tuna in water: 222 mg of EPA and DHA combined
For context, most health guidelines suggest getting at least 250 to 500 mg of EPA and DHA per day for heart health. A serving of canned albacore gets you there easily. A serving of light tuna doesn’t come close on its own. Bluefin and albacore consistently deliver the highest omega-3 levels, while leaner varieties like skipjack and yellowfin provide smaller amounts.
The American Heart Association recommends eating two 3-ounce servings of fish per week, particularly fatty fish. If you’re reaching for canned light tuna, you’re getting protein and some omega-3s, but you’d need to eat other oily fish during the week to hit meaningful omega-3 intake.
Canned Tuna: Water vs. Oil
How tuna is packed changes its fat profile. Tuna canned in water is lower in both calories and total fat. Canned albacore in water has about 3 grams of fat per 3.5-ounce serving, while light tuna in water drops to under 1 gram. Choosing tuna packed in olive oil adds fat, though it’s mostly monounsaturated rather than omega-3. If your goal is specifically omega-3 intake, water-packed albacore is the better pick.
Mercury Differs by Tuna Type Too
The fattier, larger tuna species also tend to accumulate more mercury. The FDA places canned light tuna (skipjack) in its “Best Choices” category, meaning you can safely eat two to three servings per week. Albacore and fresh tuna fall into the “Good Choices” tier, with a recommendation of no more than one serving per week. Bluefin, the fattiest and most omega-3 rich option, is a larger predatory fish that carries higher mercury levels.
This creates a trade-off: the tuna with the most omega-3s is also the tuna you should eat less frequently. For regular weekly consumption, canned albacore in water offers a reasonable middle ground, delivering solid omega-3 levels at a moderate mercury risk.
How Tuna Compares to Classic Fatty Fish
If you’re choosing tuna specifically because you heard fatty fish is good for your heart, know where it stands. Salmon, sardines, mackerel, and herring are all unambiguously fatty fish with high omega-3 levels in every form you’ll find them. Tuna is more variable. Bluefin belongs in that top tier but is expensive, less widely available, and higher in mercury. Canned albacore is a step below but still a meaningful source of omega-3s. Canned light tuna is a solid, affordable protein source, but calling it a fatty fish would be a stretch.
The simplest way to think about it: if you’re eating bluefin or albacore, you’re getting fatty fish benefits. If you’re eating skipjack or yellowfin, you’re eating a lean fish that happens to have some omega-3s. Both are worth including in your diet, but for different reasons.