Fluke vs Flounder: All You Need to Know
Apr 12, 2019 | 4 minute read Comments
Reading Time: 4 minutes

Flounder is one of America’s favorite inshore fish. It’s fun to catch, delicious to eat, and shows up all along the Atlantic and around the Gulf of Mexico. The only problem is, there’s much more than one species. Fluke vs. Flounder, Summer vs. Winter, Southern vs. Northern – it can be tough to tell which one you’ve hooked.

A close-up of a Flounder fish, focusing on its face.
It’s a Flounder, but which one?

If you’re confused about the nation’s favorite Flatfish, fear not! This article is all about the difference between Fluke and Flounder. You can learn where they live and how to tell them apart. You can also decode the various names these tasty bottom dwellers have picked up over the years.

What’s the Difference Between Fluke and Flounder?

Put simply, Fluke is Flounder. Fluke is another name for Summer Flounder, a large, predatory species of Flatfish that lives in the North Atlantic. The reason people get confused is that Winter Flounder also live in the same place. Luckily, there are some easy ways to tell the two apart.

A diagram explaining how to recognize Fluke vs Flounder. Fluke, or Summer Flounder, is above. Winter Flounder is below. The writing on the left explains that Fluke faces left and Winter Flounder faces right.

Flounder are specially adapted to a life on the bottom. So much so that one eye “migrates” across their head as they get older, until both eyes are on the same side of their face. Fluke are “left-facing,” meaning that when you hold one up, their head will be in your left hand when their eyes are above their mouth. Winter Flounder are the opposite (“right-facing”).

That’s fine when you’re holding the fish, but what if it’s in the water? Easy: Winter Flounder are darker than Summer Flounder. They can look almost black – hence their nickname, “Blackback”. Summer Flounder are light brown with cream or whitish spots. Flounders are able to change color to match their surroundings, though, so their faces are the surest way to tell them apart.

Things get a little more tricky when you come to Southern Flounder. Southern Flounder looks similar to Fluke. It’s the same size and color and it points the same way. So how do you tell them apart? Simple: spots. Summer Flounder have three ringed, eye-like spots near their tail, and several more on their back. Southern Flounder have dark patches instead, as if someone forgot to put the spots on them.

Flounder Distribution

A map showing the distribution of Southern Flounder, Fluke, and Winter Flounder on the US East Coast. Southern Flounder is marked in red, the overlap of Southern Flounder and Fluke is marked in orange, and the overlap of Fluke and Winter Flounder is marked in yellow.

Don’t worry, most of the time you won’t have to worry about telling the difference between Southern and Summer Flounder. The reason for this is that they prefer different waters. With that in mind, here’s a look at where the different Flatfish live. The key is in the name.

Southern Flounder show up along the Gulf of Mexico and up the Atlantic to southern Maryland. Fluke are also known as “Northern Flounder.” You can find them in the Carolinas, but they’re much more common north of the Chesapeake Bay. Winter Flounder live the farthest north, starting in Maryland and going up all the way to Canada.

Fluke vs. Flounder: Summing Up

There are three main species of Flounder on the East Coast. Here’s a brief summary of what makes each one special:

Summer Flounder

A happy angler in a cap standing at the back of a fishing charter boat and holding up two large Summer Flounder, also known as Fluke.
  • Summer Flounder is also known as “Fluke” or “Northern Flounder.”
  • Its head faces left when you hold it up.
  • It ringed, eye-like spots near its tail and on its back.
  • It lives from North Carolina to Maine.

Winter Flounder

A fisherman in orange waterproof trousers and a dark windproof coat holding a Winter Flounder on a boat. There are two fishing rods behind him on the right.
  • Winter Flounder is also known as “Blackback Flounder.”
  • Its head is on the right when you hold it up.
  • It is much darker than other Flounders.
  • It lives from Maryland to Labrador in Canada.

Southern Flounder

A smiling angler in a bikini and a straw hat holding a Southern Flounder on a boat.
  • Southern Flounder is “left-facing” and looks similar to Fluke.
  • It has dark patches instead of ringed, eye-like spots.
  • It prefers warmer waters than most Flounder species.
  • It lives from Maryland to Florida and in the Gulf of Mexico.

These are the main three species, but there are many more Flounders out there. Hopefully, we’ve managed to clear up some of the confusion around these delicious Flatfish. As with so many things in fishing, the best way to learn the rest is to get out there and bag one yourself!

What’s your favorite Flounder? Do you know any other ways of telling them apart? Drop us a line in the comments below, we would love to hear from you!

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Comments (2)
  • w biegel

    Jul 17, 2019

    I have always noticed that Flounders have smaller mouths (lips) versus
    Fluke which have a large mouth with an apparent lower jaw.

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      Jul 18, 2019

      Hi Biegel,

      You’re definitely right there. (Winter) Flounder seem to have smaller heads in general.

      Any other tips on telling them apart?

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