Fluke or Flounder – What is the Difference

September 15, 2011 16 Comments

Fluke or Flounder

What’s the Difference Between a Fluke and a Flounder?

One of the fun adventures my girls had on our vacation this year was going sea fishing on the commercial fishing boat Miss Avalon out of Avalon, NJ.  My wife was in charge of this particular outing as I am strictly a bay fisherman – I leave the surging swells to those with cast iron stomachs.

Turns out, my wife doesn’t have one either, but that’s another story!  You can read about their adventure at My Daughters’ Catch of the Day

Both the girls caught fish out on the Miss Avalon.  My older daughter Nell’s fish was large enough to capture second place in the boat’s pool.  First prize was cash, and Nell got a free fishing excursion to go along with her one pound sea bass.

Maddie, who was the driving force behind the deep sea fishing trip in the first place, ended up with a 3/4 pound flounder.  Or was it a fluke?  Either way, if you’ve never seen one up close and alive, it is a most…unfortunate-looking fish.

Early Life

Flukes and flounders are types of flatfish.  That means that, while they started life swimming upright, during the larval stage, they lay on either their left or right side and the eye facing towards the bottom migrated to be top-facing.

So, some flat fish are right-side-up (their left eye migrated to the right side) and some are left-side-up, meaning that their right eye migrated to the left side.  What makes a particular fish turn into a left-side or a right-side fish?

And what makes a “normal” fish evolve into a flat fish?  I honestly have no idea about the former, but I’m sure the latter adaptation was for camouflage while hunting for food.

The top side of flat fish are mottled and dark, making them blend in well on the ocean bottoms. And as they are bottom dwellers, this is a very good thing as they can surprise their unsuspecting prey.

All Fluke Are Flounder but Not All Flounder Are Fluke

Generally speaking, left-side up flounder are flukes, and right-side up flounders are called flounders.  That sounds easy enough to remember, but it gets worse.  Flukes are also called “summer flounder,” and flounder, or right-side fish, are called “winter flounder.”

It also turns out that, of the 500 plus flatfish species, there are five species that are all called flounder.  It’s good to know that there is a difference, but I would be hard pressed to taste the difference between a fluke or a flounder.

Four of the five flounder species are found in the Atlantic:  summer flounder (left-side up flukes), winter flounder, southern flounder and European flounder.  The fifth, the Japanese flounder, is found in the Pacific Ocean.

Unless you are studying fish biology, and I’m certainly not, I think the main thing to remember is that all flukes are flounders but not all flounders are flukes. And all flounder is tasty.

Fluke & Flounder Fun Facts

I did find out some kind of fun facts about flounder and fluke, though, no matter what name you call them.  Because they are so flat, large flounder and fluke (at least 8-10 pounds) are sometimes referred to as doormats or snow shoes. Finally, something about these fish that actually makes sense!

Another fun fact is that summer flounder and winter flounder are aptly named.  Summer flounder (fluke) winter off of the continental shelf and only come into the bay (to be caught) in the summer.

Winter flounder come into the bay in the fall and stay through the winter until the spring.  Sounds to me like fluke and flounder don’t like to stay around each other very much.  It could be because fluke have teeth and winter flounder don’t, but don’t quote me on that.

As to the kind of weird names: I usually think of a fluke as a freak occurrence and flounder as a verb meaning wobbling about without a way to steer.  One of the possible root words of fluke is the old German word flah, meaning flat.

I’m still not sure how something flat can also be a freak occurrence, but I don’t guess it’s every day that a fish’s eyes migrate from one side of its head to the other.

As to the name flounder, it comes from the Dutch word flodderen, which means “to flop about.”  Using that definition, all fish pretty much flounder when caught, but flounders can flop about on the bottom of the ocean, kicking up sand to cover themselves, kind of like how rays do.  Also, because they swim sideways, it can look like they don’t have a very good way to steer themselves.

No matter how they look or swim, they are very tasty when simply cooked. Here’s a recipe for broiled flounder in lemon butter and be sure to check out Pan Fried Flounder with Potatoes and Parsley. This is how my mom prepared fresh flounder for us as kids.

Broiled Flounder in Lemon Butter

Prep Time: 10 minutes

Cook Time: 10 minutes

Total Time: 20 minutes

Yield: 4 - 6 servings

Broiled Flounder in Lemon Butter


For the fish

4-6 flounder fillets

2 Tablespoons melted butter

2 Tablespoons freshly squeezed lemon juice

kosher salt and freshly ground white pepper, to taste

For serving

2-3 very thinly sliced lemon rounds per fillet

fresh Italian or curly parsley, minced

How To Prepare At Home

Rinse and pat dry the fillets. Arrange in on a baking tray.

Combine the melted butter and lemon juice and drizzle evenly over the fish, reserving about 1 tablespoon.

Lightly sprinkle with salt and pepper.

Broil the fish on the highest rack until the fish is white and is just starting to flake, about 5-7 minutes.

To serve, drizzle on the last tablespoon of lemon butter. Arrange lemon slices on each fillet and sprinkle with the freshly chopped herbs.

Last modified on Wed 22 August 2018 10:01 am

Filed in: Fish, Fish Recipes

Comments (16)

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  1. Julie says:

    Great article! My son caught a fish today…I called it a flounder, my Dad said it was a fluke! I love your play with words, and appreciate you making this an easy to read and informative blog….now i gotta go read about what size is legal to keep! TY TY TY!

  2. Leslie Thompson says:

    I grew up on the Great South Bay of Long Island NY. As I little girl I was well versed in “flounder” fishing, and then once on a bay trip with my dad I caught a big’un. As soon as I landed the fish my dad exclaimed “well, you caught a fluke!”. From that moment on, it was my understanding that a fluke is usually a much larger and heavier fish than a flounder.
    Also, when we cooked it, it tasted different to me than flounder. I really didn’t like the taste. Perhaps it’s something one gets used to?!

    • john says:

      I agree on what is Fluke or Flounder. I was in Navy stationed in NJ and fished a lot salt water even made our own Fluke or Flounder rigs, I like most newcomers to the fish was told the only difference was what side the eye was facing, But knowing how Jersey people love to joke I didn’t take it too serious, I did notice that Fluke was much larger and caught mostly at a different times and in deeper water.
      After catching both I could not swear I would know the difference,, and didn’t care as they both taste the same,, GOOd!

  3. Thunderbolt says:

    If it’s got vicious looking teeth it’s a fluke, if it has a soft toothless mouth it’s a flounder. Fluke are the tastier of the two.

  4. Lisa O says:

    Making your recipe tonight for 15!!

  5. ric bourn says:

    This is all crap. On such fish called a fluke, only by slang.
    Look it up in a dictionary.
    Get the facts before you write something.
    This is why people get in trouble fishing for flounder. There are winter and summer flounder. Along with sole another totally differant fish. Read the laws in your state before going fishing . But don’t depend on this screw up. So many believe crap like this.
    SO START IN THE DICTIONARY. Then move to the discription of flounder. Because there is no such thing as a fluke other then by Slang

    • Ric, I appreciate your enthusiasm but but if you look up “fluke” in the Merriam-Webster dictionary, it describes “fluke” as a flatfish which is exactly how I described it. I also say in big, bold letters, All Fluke Are Flounders and I also say “Flukes are also called “summer flounder,” ” so I’m sure I agree with you.

    • john says:

      You need to do more research before going ballistic, lol, I was stationed in Jersey and fished for both and made the Fluke rigs and Flounder Rigs, And have caught both,
      There is a difference but in fairness they are both same species of family.
      Fluke do get much larger, and if you check the eyes are set different , Now we get to west coast Halibut and there I am stumped,, lol

  6. Howard Petretta says:

    Wonderful article. Thank you so much for taking the time to write this. I learn something every day. Gracias

  7. denice says:

    This was wonderful. I was raised in Long island NY and my grandfather and I went to scotty’s dock and would catch fluke and flounder. He was written up in magazines in the 70’s as the Flouner Kind of Long Island Andrew Barbaccia. Thank you for they wonderful story of great fish!

  8. john says:

    I agree that many types of fish arte called different names depending on area they are in,, Like Florida call Bream and up North its a Blue Gill, A speck is a Crappie, and there jack Pike is a Grass Pike some place else, But I have been all over the east coast and in Many countries and Fluke and Flounder are two different fish not species, So don’t think there is any Fluke in the identity,, Pun Intended..lol

  9. Tom says:

    Fluke,summer flounder face left by that I mean with the mouth on the bottom and the Eyes On Top holding the fish up it’s facing left. Also it has teeth. Winter flounder face right Eyes On Top mouth on bottom and they are as toothless as your great-grandmother. All I can speak about is the Jersey Shore and summer flounder are usually always called fluke. As far as taste I personally do not see much of a difference they are both excellent fish. Well I hope I did’t confuse anyone so take care. T

  10. Linda says:

    You are the first to mention sole.

  11. Ed says:

    This is very simple a flounder is like all other fish with eyes on both sides of its body while a fluke has its eyes on one side of its body that’s why it’s referred to as a fluke. It’s all in the location of the eyes on the body. Get it. Lol

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