Flounder, Roban Kramer, CC BY-SA 2.0 , via Wikimedia Commons

Flounder: Everything You Need to Know About Paralichthys

What is Flounder?

Flounder, a name encompassing a broad spectrum of species, belongs to the flatfish family. Over 540 species are recognized, with both eyes on one side of their head in adulthood. Paralichthys lethostigma (Southern flounder) and Platichthys flesus (European flounder) are well-known species. This article provides a comprehensive overview of flounder, discussing its anatomy, ecology, reproduction, and commercial significance.


Flounders, like other flatfish, are unique for their distinctive morphology. These demersal fish, i.e., they live at or near the bottom of bodies of water, exhibit a compressed body that is laterally flat, an adaptation suitable for their benthic lifestyle. Flounders undergo an astonishing metamorphosis from the larval to juvenile stage. They are born with a symmetrical structure, akin to most fish species, but undergo changes where one eye migrates to the other side of the body, leading to an asymmetrical appearance.

In flounders, the positioning of both eyes on the same side of the body varies among species. Some have both eyes on the right (dextral or right-eyed flounder), while others have both eyes on the left (sinistral or left-eyed flounder). The side with both eyes is pigmented, typically matching the ocean floor, providing an effective camouflage from predators and prey.


Flounder species are widely distributed in the world’s oceans, predominantly in coastal and shelf waters. They exhibit a benthic lifestyle, dwelling at the sea bottom, where they can blend seamlessly into the substrate using their superior camouflage.

Their diet primarily consists of small fish, crustaceans, and other invertebrates. Flounders are ambush predators that use their camouflage to surprise prey. They lie still on the sea floor, hidden from sight, until a prey item comes within reach, upon which they strike swiftly.


Flounders follow an annual reproductive cycle. Spawning varies across species and environmental factors, such as water temperature and photoperiod. Flounder females are prolific and can produce millions of eggs per season, which are buoyant and pelagic. After hatching, larvae ascend to the water column, where they remain until undergoing metamorphosis.

As the larvae grow, they undergo a fascinating process of metamorphosis wherein their symmetrical bodies become asymmetrical. This morphological change includes migrating one eye to the other side of the body, resulting in the definitive flatfish shape.

Commercial Significance

Flounder species hold considerable economic importance. They are heavily fished globally and form a significant part of the seafood industry. Certain flounder species, such as the Japanese flounder (Paralichthys olivaceus), are commonly cultivated in aquaculture due to their popularity in culinary circles.

Flounder meat is prized for its mild flavor, firm texture, and low-fat content. These characteristics make it a versatile culinary component used in various cuisines worldwide. However, The industry’s sustainability faces challenges due to overfishing and habitat degradation.

Conservation and Threats

Overfishing, habitat loss, and climate change pose significant global threats to flounder populations. Sustainable fishing practices are necessary to ensure these species’ long-term survival and viability. 

Additionally, understanding the effects of climate change on flounder populations is crucial, as changing sea temperatures and acidity levels can affect their spawning and overall population dynamics.

How to Cook Flounder

Baked Flounder with Parmesan Crumbs


  • 4 flounder fillets
  • 1/2 cup grated Parmesan cheese
  • 1/4 cup butter, softened
  • 3 tablespoons mayonnaise
  • 2 tablespoons lemon juice
  • 1/4 teaspoon dried basil
  • 1/4 teaspoon ground black pepper
  • 1/4 teaspoon paprika
  • 1/4 teaspoon onion powder
  • 2 tablespoons breadcrumbs


  1. Preheat your oven to 350 degrees Fahrenheit (175 degrees Celsius).
  2. Arrange the flounder fillets in a baking dish that has been lightly greased or lined with parchment paper.
  3. Combine the Parmesan cheese, butter, mayonnaise, and lemon juice in a bowl. Stir until well mixed.
  4. Add the basil, black pepper, paprika, and onion powder to the bowl. Stir to combine.
  5. Spread the cheese mixture over the flounder fillets. Sprinkle with breadcrumbs.
  6. Bake in the preheated oven for about 20 minutes, or until the fish flakes easily with a fork. The top should be golden and bubbly. Serve warm.

Pan-Fried Flounder with Lemon-Butter Sauce


  • 4 flounder fillets
  • Salt and black pepper
  • 1/2 cup all-purpose flour
  • 4 tablespoons unsalted butter, divided
  • 1 tablespoon olive oil
  • 2 cloves garlic, minced
  • Juice of 1 lemon
  • 2 tablespoons chopped fresh parsley


  1. Season both sides of the flounder fillets with salt and black pepper.
  2. Dredge the fillets in flour, shaking off any excess.
  3. In a large pan, melt 2 tablespoons of the butter with the olive oil over medium-high heat.
  4. Add the flounder fillets and cook until golden brown, about 2-3 minutes per side. Remove the fillets and set them aside.
  5. In the same pan, add the minced garlic and cook until fragrant.
  6. Add the lemon juice to the pan, scraping any browned bits from the bottom.
  7. Stir in the remaining 2 tablespoons of butter until melted and combined with the lemon juice.
  8. Pour the lemon-butter sauce over the flounder fillets, sprinkle with chopped parsley, and serve.

Enjoy these delicious flounder dishes!


Flounder, with their unique morphology, lifestyle, and economic significance, are remarkable organisms that contribute greatly to the complexity and diversity of marine ecosystems. Understanding their biology, ecology, and the threats they face is crucial for their sustainable management and conservation. As we continue to study and understand these fascinating creatures, we can further appreciate their role in the ecosystem and our shared world.

Frequently Asked Questions about Flounder

1. Is flounder healthy?

Yes, flounder is considered a healthy choice for most people. It is low in fat and high in protein. Flounder is also a good source of vitamins like B12, B6, niacin, and minerals such as magnesium and selenium.

2. How to fillet a flounder?

Filleting a flounder involves a specific technique due to its flat body shape. Start by cutting just behind the gills until you reach the backbone. Then, turn your knife sideways and run it along the backbone, cutting towards the tail. Repeat this process for all four sections (two on each side) of the flounder.

3. How to catch flounder?

Flounder can be caught using various methods, but they’re most commonly caught with a rod and reel using live bait such as minnows or shrimp. They are bottom-dwelling fish, so ensure your bait is near the seabed.

4. Is flounder kosher?

Yes, flounder is considered kosher because it has fins and scales, the two requirements for fish to be deemed kosher according to Jewish dietary laws.

5. Does flounder have scales?

Yes, flounder have small, smooth scales that are not readily apparent due to their camouflaging skin.

6. Does flounder have bones?

Like most fish, flounder have a bone structure, including a central spine and numerous smaller bones.

7. Is flounder fishy?

Flounder is known for its delicate, sweet flavor and is not typically described as “fishy.” Its mild taste makes it a versatile ingredient in many dishes.

8. Can dogs eat flounder?

Yes, dogs can eat flounder. However, it should be cooked and deboned to prevent potential pet harm. As with any human food, it should be given in moderation, not replace a balanced dog diet.

9. How to clean flounder?

To clean a flounder, you’ll need to scale it, gut it, and then rinse it thoroughly under cold water. Scaling can be done with the back of a knife, and the gutting process involves a cut from the anus to the head to remove the internal organs.

10. Is flounder a bottom feeder?

Yes, flounder are considered bottom feeders. They have a unique camouflage ability that allows them to blend into the ocean floor while they wait for prey.

11. Is flounder a white fish?

Yes, flounder is a type of white fish. When cooked, it has a delicate, mild flavor and a white, flaky texture.

12. Is flounder high in mercury?

Flounder is generally lower in mercury than larger predatory fish like swordfish or tuna. It is considered a safer choice for frequent consumption.

13. How big do flounder get?

The size of flounder can vary greatly depending on the species. On average, they can grow between 12.5 to 37.5 cm in length. However, some larger species, like the Atlantic flounder, can reach up to 60 cm.

14. Can pregnant women eat flounder?

Yes, flounder is generally safe for pregnant women to eat due to its low mercury content. However, it should be properly cooked to avoid any risk of foodborne illnesses.

15. When is flounder in season?

Flounder can be found year-round, but they’re generally plentiful during fall and spring migrations.

16. What is the difference between fluke and flounder?

“Fluke” is a common name for summer flounder. While fluke and flounder belong to the flatfish family, they are different species. The fluke has a larger mouth with sharp teeth and is typically more aggressive than other flounder species.

17. Can you eat flounder raw?

Yes, flounder can be eaten raw and is often used in sushi and sashimi. However, it must be fresh and properly handled to reduce the risk of foodborne illnesses.

18. How much protein in flounder?

A 3.5-ounce serving of flounder provides around 24 grams of protein, making it an excellent source of lean protein.

19. How to catch flounder with artificial bait?

Flounder can be caught with artificial bait such as soft plastics or jigs. The key is to mimic the movement of their natural prey, moving the bait slowly along the bottom of the water.

20. How to make flounder rigs?

A common rig for flounder fishing is the fishfinder rig. To make this, you’ll need a sliding fishfinder, a 24-36 inch leader, a hook, and a sinker. Thread your line through the fishfinder, then tie a swivel to the end of the line. Attach your leader to the other end of the swivel, then attach your hook to the end of the leader. The sinker goes on the fishfinder to keep your bait near the bottom.

Similar Posts