What Are the Best Fatty Fish to Eat on a Ketogenic Diet?

Fish is an excellent source of protein and omega-3 fatty acids on any diet, and it fits perfectly into a ketogenic diet. If you’re a pescatarian on the keto diet, you have an advantage over keto vegetarians: you get to eat fish as a source of fat and protein. It’s not uncommon for keto dieters to get bored with the constant chicken and bacon they end up consuming. However, some fishes are a better source of fat than others, and when your body is using fat for fuel, it’s important to know which fishes will be best for sustaining you.

This article explores different types of fish and determines whether each is considered a fatty fish and is beneficial on the keto diet. We’ll start out with the fattiest fishes and then discuss a few types of fish that have low fat content. Whether you’re a pescatarian or meat eater, you should find this article helpful when shopping for your keto groceries. You may also want to bookmark my pescatarian keto food shopping list when you are planning your next grocery trip.

Best Fatty Fish for Keto: Quick Comparison

Fish	Keto fit	Fat level	Protein	Mercury note	Best use
Salmon	Excellent	High	High	Generally lower mercury	Fresh meals, canned salmon, salads
Sardines	Excellent	High	High	Lower mercury	Pantry staple, snacks, salads
Atlantic mackerel	Excellent	High	High	Lower mercury than king mackerel	Canned or fresh meals
Anchovies	Good	Moderate-high	Moderate-high	Lower mercury	Toppings, snacks, sauces
Herring	Excellent	High	High	Generally lower mercury	Smoked, pickled, canned
Trout	Good	Moderate-high	High	Lower mercury	Fresh meals
Sablefish / black cod	Excellent	High	High	Varies by source	Rich dinner fish
Cod	Keto-friendly but lean	Low	High	Lower mercury	Add fat when cooking
Tilapia	Keto-friendly but lean	Low	High	Lower mercury	Add fat when cooking
Catfish	Keto-friendly but lean	Low-moderate	High	Usually lower mercury	Add fat when cooking

Is salmon a high fat fish?

Yes, salmon is considered a fatty fish. A 6 oz serving of salmon contains 22g of fat, 34g of protein, and 354 calories according to USDA FoodData Central. It is important to note, however, that fat content in a cut of salmon can vary. A major positive of salmon is that it is very rich in omega-3 fatty acids. King salmon have the most fat of any type of salmon and also the most omega-3. Fresh salmon has a higher omega-3 content than canned salmon, but the amount of omega-3 in canned salmon is still significant compared to other foods.

Salmon is very popular and is well-known as one of the best foods you can eat on the keto diet. Keto dieters typically try to select fattier cuts of salmon and also usually eat more than the recommended serving size. Canned salmon may be more affordable than fresh salmon and contains many of the same health benefits although the nutritional value may be slightly lower. If you are eating a lot of omega-6 on the keto diet due to consuming large amounts foods like nuts and certain oils, the omega-3 from salmon can help to balance it. A proper balance of omega-3 and omega-6 fatty acids is vital for health, and eating significantly more sources of omega-6 than omega-3 should be a concern.

Are sardines considered fatty fish?

Sardines are considered a fatty fish, with the average 3.75 oz can containing 11g of fat and 23g of protein. Sardines canned in oil will contain more fat than sardines canned in water, so many people eating a high fat low carb diet opt for sardines in olive oil. However, sardines in water are more ideal if you are trying to optimize your omega balance. Sardines are a great source of omega-3 fatty acids, but adding oil also adds omega-6.

Canned sardines are a common keto food. Most contain zero carbs, although some are canned in tomato sauce or with fruits and vegetables like olives and peppers. This may add a very small amount of carbohydrates but should still fit easily within your keto macros. Wild Planet sardines, which are sustainably caught, are the brand keto expert Dom D’Agostino often mentions on his podcast appearances. Canned sardines with skin and bones are healthier because of their calcium content. If you are new to sardines and hesitant about eating the whole fish, you can opt for skinless sardines and still get most of the benefits. Sardines are especially tasty when sauteed with low carb vegetables such as spinach but can also be a convenient snack straight out of the can.

Are anchovies a good fatty fish for keto?

Anchovies are an oily fish with decent fat content. A 2oz can of anchovies contains 4.4g of fat and 13g of protein according to USDA FoodData Central. Anchovies are not as high in omega-3 fatty acids as salmon, but they are still an excellent source. While anchovies are traditionally known as a pizza topping that people either love or hate, many keto dieters like to eat them right out of the can.

Is mackerel a high fat fish?

Mackerel is a fatty fish with omega-3 fatty acid levels that compete with salmon. A 90g serving of mackerel contains about 16g of fat and 17g of protein. King mackerel and Spanish mackerel contain higher levels of mercury than Atlantic mackerel, making Atlantic a wiser choice. A major benefit of mackerel is that it is more affordable than salmon. If you can’t get your hands on fresh mackerel, canned mackerel is available.

Is herring good for keto?

Yes, herring is a good fatty fish for keto. It is naturally low in carbs, higher in fat than lean white fish, and works well smoked, pickled, or canned. If you buy pickled herring, check the label because some preparations include sugar. Smoked or canned herring is often easier to fit into keto macros.

Is trout good for keto?

Yes, trout can be a good keto fish. It is not always as fatty as salmon or sardines, but it is usually higher in fat than very lean white fish like cod or tilapia. Trout is also a helpful option if you want a fresh fish dinner that still gives you plenty of protein.

What about sablefish or black cod?

Sablefish, also called black cod, is an excellent fatty fish for keto because it is rich, tender, and naturally high in fat. It is usually more expensive than salmon, sardines, or canned mackerel, but it can be a great dinner fish if you want something satisfying without adding a heavy sauce.

Best Canned Fatty Fish for Keto

Canned fish is one of the easiest ways to keep pescatarian keto meals simple. It is shelf-stable, usually affordable, and does not require cooking, which is helpful if you want keto food available before you are already hungry.

• Canned salmon: Good for salmon salad, lettuce cups, keto patties, and quick bowls.
• Sardines: One of the easiest fatty fish options to keep in your pantry, especially sardines packed in olive oil.
• Anchovies: Strong flavor, but useful in salads, sauces, eggs, and low-carb vegetable dishes.
• Canned mackerel: A good salmon alternative if you want fatty fish that is often more budget-friendly.

If you are buying canned fish for keto, check the label for added sugars or sauces. Fish packed in olive oil, water, or its own juices will usually be the easiest to fit into your macros. For more pantry ideas, see my pescatarian keto food shopping list.

Now, we’ll move onto a few types of fish that people may not realize are actually very low in fat.

Is cod a high fat fish?

No, cod is not a high fat fish. In fact, it is typically classified with lean fishes including bass, flounder, and halibut. A 3oz fillet of cod contains less than 1g of fat but may have as much as 15-20g of protein. If you are on a low carb high fat diet, you’re unlikely to choose cod to help you hit your fat macros, but it’s an excellent source of protein. Plus, cooking any fish in butter or oil increases the fat content.

Is tilapia a high fat fish?

No, tilapia is a low fat fish rather than a high fat fish, but it is a good source of protein. In a 100g serving of tilapia (3.5oz), you’ll find a mere 1.7g of fat and a significant 20g of protein. If you are trying to limit the amount of calories you’re eating, tilapia is a great choice with only 96 calories per 100g serving. However, if you are on a ketogenic diet and need to eat more fat, tilapia won’t help much unless you cook it in a lot of fat.

Is catfish high in fat?

No, catfish is considered a lean fish that is not high in fat content. A 3oz serving of catfish contains 6g of total fat and 15.7g of protein, so it’s a much more significant source of protein than fat. While catfish is rather low in fat, it is not quite as low as cod and tilapia. The low fat content of catfish results in it being very low calorie with only 122 calories in a 3oz fillet. Like any fish, catfish is an excellent low carb choice for the keto diet, but it’s necessary to cook it in fat if you want your catfish dinner to contribute to your daily fat macros in a significant way.

How to Make Lean Fish Work on Keto

Lean fish can still fit a ketogenic diet because fish contains little to no carbohydrate. The main difference is that lean fish will not do much to help you hit your fat target unless you add fat to the meal.

Good ways to make lean fish more keto-friendly include:

• Cooking it in olive oil, avocado oil, butter, or ghee
• Serving it with avocado or olives
• Adding a mayo-based sauce, pesto, or aioli
• Pairing it with low-carb vegetables tossed in oil
• Using a cream-based sauce if you include dairy

Cod, tilapia, catfish, haddock, pollock, and mahi-mahi can all work on keto. They just need help from the fat department. If you are not sure whether your meal is giving you enough fat, protein, or carbs for the day, use the keto macro calculator to estimate your targets.

Which Keto-Friendly Fish Are Lower in Mercury?

Since many keto-friendly fish are seafood staples people may eat often, it is worth paying attention to mercury. The FDA and EPA advice about eating fish groups fish into “Best Choices,” “Good Choices,” and “Choices to Avoid.” Salmon, sardines, anchovies, Atlantic mackerel, cod, tilapia, and catfish are listed as “Best Choices,” while king mackerel is listed as a fish to avoid because of higher mercury levels.

That does not mean you need to panic about seafood. It just means that if you eat fish frequently, you may want to favor lower-mercury options like salmon, sardines, anchovies, Atlantic mackerel, trout, cod, tilapia, and catfish while limiting higher-mercury fish like king mackerel, swordfish, shark, bigeye tuna, marlin, orange roughy, and tilefish from the Gulf of Mexico. If you are using fish as a staple food while trying to stay in ketosis, choosing lower-mercury options most of the time is a practical way to keep your routine sustainable.

Fatty Fish vs. Lean Fish for Keto

A few other common lean fishes that can work on keto when you add fat are:

• Sea bass or grouper
• Haddock
• Monkfish
• Skate
• Pollock
• Mahi-mahi
• Flounder

What is your favorite fatty fish to eat on the keto diet? Do you ever eat lean fishes like cod, tilapia, and catfish, or do you avoid them in favor of fattier fishes? I’d love to hear your thoughts in the comments below! Plus, feel free to share any delicious keto fish recipes you love. For more current grocery ideas, see my pescatarian keto food shopping list.

Frequently Asked Questions About Fatty Fish on Keto

What is the best fatty fish for keto?

Salmon, sardines, mackerel, anchovies, herring, trout, and sablefish are some of the best fatty fish for keto because they are low in carbs, high in protein, and higher in fat than lean white fish.

Are sardines good for keto?

Yes. Sardines are a very keto-friendly fish because they are low in carbs, rich in protein, and naturally high in fat. Sardines packed in olive oil are especially easy to use as a high-fat keto pantry food.

Is canned fish good for keto?

Yes. Canned salmon, sardines, anchovies, tuna, and mackerel can all fit a keto diet. Check the label for added sugars, sauces, or fillers, especially with flavored varieties.

Is cod keto-friendly?

Cod is keto-friendly because it is very low in carbs and high in protein. However, cod is lean, so it will not contribute much fat unless you cook it with oil, butter, or a high-fat sauce.

What fish should I avoid on keto?

Most fish can fit keto from a carb perspective, but you may want to limit high-mercury fish if you eat seafood often. The FDA lists king mackerel, swordfish, shark, bigeye tuna, marlin, orange roughy, and Gulf of Mexico tilefish as choices to avoid because of mercury.

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