A 3-ounce serving of cooked fish (roughly the size of a deck of cards) contains between 70 and 200 calories, depending on the species. Leaner white fish like cod and tilapia sit at the low end, while fattier fish like salmon and mackerel land higher. Beyond the type of fish, how you cook it and how it’s packaged can easily double the calorie count.
Calories by Fish Type
Fish fall into two broad categories: lean and fatty. Lean fish store very little fat in their flesh, keeping calories low. Fatty fish carry more omega-3-rich oils, which adds calories but also delivers significant nutritional benefits. Here’s how common varieties compare for a 3-ounce cooked serving:
- Cod: about 70–90 calories
- Tilapia: about 110 calories
- Grouper: about 100 calories
- Skipjack tuna (fresh): about 110 calories
- Coho salmon (wild): about 120–150 calories
- Chum salmon: about 120–130 calories
- Atlantic salmon (farmed): about 175–200 calories
- Mackerel: about 170–230 calories, depending on species
The calorie gap between the leanest and fattiest fish is substantial. You could eat a full 3-ounce portion of cod for fewer calories than half a portion of farmed Atlantic salmon. That said, the extra calories in fatty fish come almost entirely from heart-healthy fats, not from anything nutritionally empty.
Why Fish Is So Protein-Dense
One reason fish stands out among protein sources is how much protein you get relative to the calories. A 3-ounce serving of skipjack tuna delivers nearly 24 grams of protein. Wild coho salmon provides about 23 grams, grouper about 21 grams, and even relatively mild fish like chum salmon clocks in around 22 grams per serving. That’s comparable to chicken breast, and often with fewer total calories.
This protein density is why fish shows up in so many weight-management plans. You get a large share of your daily protein needs from a relatively small, low-calorie portion. For context, a 3-ounce serving of most fish provides 40–50% of the average adult’s daily protein target.
How Cooking Changes the Count
The preparation method can matter more than the fish you choose. A 100-gram portion of grilled cod contains roughly 105 calories. That same portion fried in batter jumps to 200–250 calories or more. That’s a potential 140% increase just from the cooking method.
Fried fish absorbs anywhere from 8–25% of its weight in oil during cooking. The exact amount depends on batter thickness, oil temperature, and frying time. A thin, crispy coating at high heat absorbs less than a thick, soggy batter cooked at lower temperatures. But even a well-executed fry adds meaningful calories compared to grilling, baking, or steaming.
If you’re tracking calories closely, these are the lowest-calorie preparation methods, roughly in order: steaming, poaching, baking or roasting without added fat, grilling, pan-searing with a small amount of oil. Once you add breading, butter sauces, or deep frying, you’re no longer really eating a “low-calorie” protein, regardless of which fish you started with.
Canned Fish: Water vs. Oil
Canned tuna is one of the most common ways people eat fish, and the packing liquid makes a dramatic difference. A 5-ounce can of chunk light tuna packed in water contains about 120 calories. The same tuna packed in oil jumps to 280 calories. That’s more than double, from a product that looks nearly identical on the shelf.
Draining the oil helps somewhat, but the fish still retains a significant amount of absorbed oil. If calories are your main concern, water-packed tuna is the clear winner. Oil-packed versions do have a richer flavor and slightly different texture, which some people prefer for salads or pasta dishes. Just know what you’re getting: the convenience of canned fish doesn’t automatically mean it’s low-calorie.
How Much Fish to Eat Per Week
The Dietary Guidelines for Americans recommend 8 ounces of seafood per week for adults on a 2,000-calorie diet. That works out to roughly two or three servings, depending on portion size. Meeting this target with lean fish like cod or tilapia adds only 200–300 calories to your weekly total, while choosing fattier fish like salmon might add 400–500 calories but provides substantially more omega-3 fatty acids.
If you’re eating fish primarily as a low-calorie protein source, white fish grilled or baked is your best option. If you’re eating it for the broader health benefits (particularly heart and brain health from omega-3s), fattier fish like salmon, sardines, and mackerel are worth the extra calories. For most people, alternating between lean and fatty varieties across the week strikes a practical balance between keeping calories in check and getting the nutritional payoff fish is known for.