Halibut vs. Flounder: 5 Differences & Which Is Better?

Halibut and flounder are both excellent protein options; however, one may be better than the other, depending on your overall goals.

So what are the differences between halibut vs. flounder? The main differences between halibut and flounder are that halibut is higher in calories (+ 21 calories) and protein (+6.2 grams), and it’s more anti-inflammatory with two times more omega-3 content than flounder.

As a Registered Dietitian, it is my job to educate my clients on which food options are the best for their health based on their goals.

In this article, I will dig into the differences between halibut and flounder to help you determine the best option for you.

Halibut vs. Flounder: Nutritional Information

Halibut vs. Flounder Nutritional Information

To determine whether Halibut or Flounder is better, it’s important to compare their nutritional information to see where the differences lie.

The following table gives you the nutritional information for 100 g of raw halibut and flounder

Carbs (g)00
Protein (g)18.612.4
Fats (g)1.31.9
Saturated fats (g)0.30.3
Monounsaturated fats (g)0.70.2
Polyunsaturated fats (g)0.70.3
Omega-3 (mg)522253
Omega-6 (mg)308


Halibut is higher in calories (+21 kcal) than flounder, which makes flounder a better option for those trying to lose weight and halibut a better option for those with a higher caloric intake.

Although a 21 calories difference might not seem like much, when it comes to losing weight, 21 calories could be the difference between you feeling hungry or not because you’ll be eating lots of low-calorie, high-volume foods.

That being said, the type of fish you choose won’t make or break your diet because you can gain weight while eating flounder and lose weight while eating halibut, as long as your calorie intake aligns with your goals.


The nutritional information also reveals that halibut is higher in protein than flounder, by 6.2 grams, so if you struggle to meet your protein requirements, halibut is a better option.

Protein plays an important role in your body since it helps support your muscle mass, increase your metabolism, and increase your fullness levels. 

If you have difficulty reaching your protein requirements, halibut is the better option for you. However, if you prefer the taste of flounder over halibut, you could increase your portion size of flounder to achieve the same protein intake. 

For example, if you have 100 g of halibut, which has 18.6 g of protein, you’ll need 150 g of flounder to have the same amount of protein (18.6 g).


Halibut and flounder have similar amounts of fat, with flounder having only 0.3 g more total fat than halibut.

Halibut and flounder are both considered lean protein options with a low saturated fat content, which is important because a high intake of saturated fat could lead to heart disease. 

Of their fat content, only 0.3 grams are from saturated fat, which makes them both heart-healthy protein sources.


One of the big differences between halibut and flounder is their micronutrient profiles, with halibut being higher in vitamins and minerals than flounder.

It’s important to note that 5% or less represents a minimal amount of that nutrient in the following table, and 20% or more indicates a significant amount.

NutrientHalibut - Daily Recommended Value in 100g portionFlounder - Daily Recommended Value in 100g portion
Vitamin A3%1%
Vitamin C0%3%
Vitamin D-15%
Vitamin E4%3%
Vitamin K0%0%
Vitamin B617%10%
Vitamin B1220%25%

The Top Nutrients In Halibut & Their Benefits:

  • Niacin. It has a crucial role in converting the food you eat into usable energy by the body. 
  • Magnesium. It can help boost performance since it reduces the risk of muscle cramps. In a study, women with a greater magnesium intake had an increase of 26% in their power (strength). 

Halibut also has a significant amount of Vitamin B12 but not as much as flounder does.

The Top Nutrients In Flounder & Their Benefits:

  • Selenium. Selenium is a powerful antioxidant that can help reduce inflammation in your body. Additionally, it plays a crucial role in your immune system. Your immune response can decrease without adequate selenium levels, making you more prone to illnesses. 
  • Vitamin B12. It seems that vitamin B12 can have an impact on your mood. Studies show that those with vitamin B12 deficiency were twice as likely to suffer from depression compared to those with normal blood levels of this vitamin. 

Halibut vs. Flounder: 5 Differences

Halibut vs. Flounder 5 Differences

1. Taste and Texture

Flounder and halibut have very similar tastes because they’re both lean fish, so they don’t have an oily flavor. However, they differ in texture because halibut has a firmer texture, while flounder has a more flaky texture (like tilapia). 

While they have different textures, they both pair nicely with any herb, spice, or sauce you choose, so they can be substituted for each other in recipes as far as taste goes.

Winner: Tie

When it comes to taste and texture, I’m declaring a tie because I enjoy them both equally, but this is mainly personal preference.

2. Cooking Methods

While all cooking methods are appropriate for halibut and flounder, certain dishes are better suited to one fish over the other because halibut has a firmer texture than flounder.

Halibut and flounder can both be pan-fried, air-fried, or baked, but if you’re making a dish like fish sticks that you don’t want to fall apart, then halibut is a better option than flounder.

Another difference in cooking methods between halibut and flounder is that halibut generally cooks in 10 minutes while flounder can take up to 15 minutes. For those with limited time to prepare their meals, a 5-minute difference in cooking time could be significant.

Winner: Halibut

Halibut is the winner in cooking methods because it can be used in more dishes than flounder and cooks around 5 minutes faster.

3. Costs

One of the most significant differences between halibut and flounder is that halibut is $10 more expensive than flounder.

In the following table, you can compare the price of halibut and flounder from each of the biggest grocery stores in the US. The prices are given per pound of product. 

Fish (1lb)WalmartCostcoTargetWhole Foods

Besides the price, an important aspect to consider is the availability of each fish. Flounder is harder to come by even in large grocery stores, whereas halibut is readily available.

Winner: Flounder

Flounder is the winner because it’s significantly cheaper than halibut; however, it’s also harder to obtain than halibut.

However, if flounder isn’t available where you live, then Halibut would be the better choice.

4. Omega-3 and Omega-6

Another difference between halibut and flounder is the amount of Omega-3 & Omega-6 fats each contains. These fats are essential because your body cannot produce them, so you must rely on food sources to obtain them. 

Omega-3 fatty acids provide anti-inflammatory properties in your body, while omega-6 fatty acids are pro-inflammatory

That said, your body needs some inflammation to help in specific processes (for example, signaling your immune response). The problem with inflammation arises when you have more inflammation than your body can handle.

Therefore, your intake of Omega-3 fatty acids should be higher than your intake of Omega-6 fatty acids.

Halibut has twice the omega-3 content of flounder with 522 mg compared to 253 mg. However, both fish are low in omega-6. 

Winner: Halibut

Halibut is the winner because it has twice the amount of omega-3 than flounder, and it’s also low enough in omega-6 to be considered a heart-healthy option. 

5. Mercury

One important difference to consider between halibut and flounder is their amount of mercury. Adding too much mercury to your diet could lead to mercury poisoning with symptoms like fatigue, headache, depression, memory problems, and tremors

The type and the amount of fish you consume play a crucial role in how much mercury you get in your diet. The FDA classifies the fish whether they are the best choice (low mercury), the good choice (some mercury), and fish to avoid (high mercury)

According to the table, halibut is placed in the “good choice” category, meaning it has some mercury. Therefore, limiting your consumption of halibut to twice a week is recommended.

On the other hand, flounder is in the “best option” category, meaning you can consume it 2-3 times per week without drastically increasing your risk of mercury positioning.

Winner: Flounder

The fish with the lowest mercury content is flounder and can therefore be consumed more frequently than halibut.

Halibut vs. Flounder on Environmental Sustainability

It’s also important to consider each fish’s impact on environmental sustainability. Both flounder and halibut can be farm-raised or wild-caught, so there is an option to encourage sustainability if you choose wild-caught varieties.

There are two ways to obtain fish: wild-caught or farmed-raised. 

Farmed-raised fish are bred in tanks set in the ocean or rivers. In most cases, these tanks are small, creating a stressful environment for the fish. Also, they are more likely to catch a disease since they are grouped. 

Fish prone to disease need to be given antibiotics, which leads to overexposure to antibiotics. These antibiotics then travel to the farm’s wildlife because the fish are used as a food source.

On the other hand, wild-caught fish have fewer environmental impacts, and studies have shown that they can have 50% more omega-3 fatty acids compared to farmed-raised ones. 

When possible, opt for wild-caught fish rather than farm-raised fish to promote sustainability and better nutrient quality.

Halibut vs. Flounder on Different Diets


Although halibut and flounder are both excellent protein sources, they are both relatively low in fat, which is the primary nutrient for the keto diet. Therefore, neither halibut nor flounder is an ideal option for the keto diet.

For the keto diet, you will need around 70-80% of your total calories from fat. Since halibut and flounder are low in fat, you would need to add high-fat sources like butter, avocado, oils, olives, nuts, and seeds to compensate for these fish on the keto diet.


On a paleo diet, your primary goal is to reduce your body’s inflammation, which can be achieved by consuming a higher intake of omega-3 fatty acids. Since halibut has twice the omega-3 content than flounder, it is a better option for those following this lifestyle. 

If you are going to include flounder, include high omega-3 food sources like chia seeds or flaxseeds to compensate for the lower content of omega-3. 

Intermittent Fasting 

With intermittent fasting, you’re trying to fit all your daily nutrition into a shorter time frame, so it can be challenging to get enough protein in to retain your muscle mass.

To keep your protein levels high during intermittent fasting, adding options like flounder or halibut can help you achieve your total protein intake. An adequate protein intake can help preserve your muscle mass and keep you fuller for longer.

Low-Sodium Diet

Fresh flounder and halibut are great options for a low sodium diet because they’re both very low sodium foods. 

Typically fish are higher in sodium when canned, but it’s challenging to find flounder and halibut in canned versions. If you find a canned version of these fish, make sure that it has less than 140 mg of sodium per serving; that way, it would still be an excellent low-sodium option.


Neither of these is a suitable option for a vegan or vegetarian diet. If you’re looking for an alternative, try seaweed or tofu. 


With a low FODMAP diet, you need to be mindful of the carbs you consume since they can irritate your gastrointestinal tract. Since halibut and flounder don’t contain carbs, they are naturally low in FODMAPs, making them an ideal food for irritable bowel syndrome (IBS). 

That being said, you should be mindful when cooking these fish because often, the foods you would use to flavor these fish or the foods you’re pairing them with are high in FODMAPs, like garlic and onions.

Halibut vs. Flounder: Which Is Better For Weight Loss?

Both halibut and flounder are excellent choices for weight loss because they’re low in calories and high in protein. However, halibut is better since it is higher in protein than flounder. 

Protein plays a crucial role in weight loss. It helps maintain your muscle mass, increases your fullness levels (avoiding getting hungry while reducing your calories), and helps to increase your metabolism (meaning you burn more calories). 

Since halibut has 6.2 g more protein than flounder, it is a better choice during weight loss. However, if you choose to include flounder, then make sure to add more protein in your other meals to compensate for the lower protein content of the flounder itself.

Halibut vs. Flounder: Which Is Better For Muscle Gain?

While they have a similar caloric content, halibut is a better option for weight gain because it has 21 more calories than flounder. It also has a higher protein content (+6.2 g), which can help you to build additional muscle mass.

Although halibut is higher in calories than flounder, they’re both still considered low-calorie proteins because they’re low in fat and therefore don’t have as many calories as a fattier fish like salmon. 

Because these fish are lower in calories, you must include other high-calorie foods like butter, avocado, and olive oil to help you reach a caloric surplus (eating more calories than your body needs to maintain weight).

Practical Recommendations: Eating Halibut vs. Flounder

Practical Recommendations Eating Halibut vs. Flounder

Mix Them Up

From a nutritional standpoint, it’s best to increase the variety of nutrients that you’re getting by mixing up your protein sources. Doing so makes you less likely to become deficient in essential nutrients.

I recommend having halibut one day and flounder the next or rotating week to week rather than day to day. You could also add other protein options like tuna, tilapia, salmon, mahi mahi, or cod. 

Choose The One You Like

Another recommendation I’ll make is never to push yourself to eat something you hate, even if it’s incredibly nutritious. If you dislike halibut or flounder, you don’t need to eat it.

Eating should be a pleasant experience and not something you force yourself to do; there will always be another alternative for food you don’t enjoy, so don’t stress yourself out about a particular food.

Track Your Food

I also recommend that you consider tracking your calories and macros to ensure that you hit your nutritional targets based on your goals.

As mentioned before, halibut and flounder have a similar caloric content but very different protein content. 

Tracking can be helpful to determine how much protein you need to add to your other meals if you’re choosing to mix it up and have flounder rather than halibut.

The best way to ensure you get enough protein throughout the day is to track it.

Cook Them In Different Ways

Learning how to prepare halibut and flounder is important so that you feel confident including them in your diet more often.

As I mentioned, halibut and flounder pair well with various herbs and spices and can be cooked in multiple ways.

My favorite recipes for flounder and halibut are:

Other Fish Comparisons

About The Author

Brenda Peralta

Brenda Peralta is a Registered Dietitian and certified sports nutritionist.  In addition to being an author for FeastGood.com, she fact checks the hundreds of articles published across the website to ensure accuracy and consistency of information.

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