Best known for their unique body shape, flounders are a group of flatfish. They prefer coastal areas, spending their lives near North America, Europe, Africa, and Asia.
Like all flatfish, including halibut, sole, and turbot, flounders have “twisted” faces, with both of their eyes on the same side of their head.
For that reason, the different species fall under the right-eye or left-eye categories. Other differences can help distinguish one species from another. Keep reading to learn more about the different types of flounder.
More commonly known as a fluke, the left-eyed summer flounder is a dark grey, drab green, or brown fish with black “eye” spots and a white belly, though they can change their hue and pattern to match their surroundings.
This species lives on the sandy floor of the western Atlantic Ocean, roaming as far north as Nova Scotia and as far south as Florida.
Females are larger than males, the former of which can reach lengths of 3-feet, while the latter averages around 2-feet.
Summer flounders are avid ambush predators and capable of sprint swimming. They use their chameleon-like camouflage to hide in plain sight from their prey before snapping them up in their razor-sharp teeth—crabs, shrimp, and other small ocean creatures that happen across them.
The black back, or winter, flounder are around 2-feet long and weigh 3-8 pounds. They are predominately black right-eyed fish, though they can change to red, olive, and brown shades.
Like the summer flounder, their belly is white. Their habitat is the Atlantic Ocean, ranging from Canada to North Carolina.
While they look very similar to summer flounder, winter flounder has much smaller teeth than their counterpart and eyes on the opposite side of their head.
Because their mouths are smaller, they cannot consume the same diet. For that reason, they mainly eat larval crustaceans, phytoplankton, and marine worms.
The Southern Flounder is another example of a left-eyed flatfish. The species shows sexual dimorphism, as the female grows twice as long as the male, typically around 12-inches in length.
They spend their lives in the Western Atlantic and the Gulf of Mexico. Southern flounders are a rich brown color, with irregular, darker splotches.
Their habit of spending time near schools of shrimp has led to overfishing, as they get caught up in the nets.
What sets the southern flounder apart from summer and winter flounder is the irregularity of their spotting.
While the other two species have ocellated, or “eyelike,” spots, this particular flounder is unocellated.
Like its name would imply, Gulf flounder swim the waters of the Gulf of Mexico near Florida and Texas. It is a left-eyed flounder that grows up to 2-feet long.
When not camouflaged, Gulf flounders are reddish-brown and covered in blotchy spots. They have short, paddle-like tails that facilitate their movement through the sand.
The most prominent feature of the Gulf flounder is their three dark eyespots that form a triangle on the darker side of their body. Two spots near the head start the base, while a final spot above the tail completes the trio.
American plaice, a right-eyed fish, trawl both sides of the Atlantic Ocean, from the southern part of Greenland to New England in the west and from northern Finland to the English Channel in the east.
They prefer colder temperatures and grow to only a foot long. Females can live very long lives, up to 20 years.
They are lighter-colored than many other flounder species, presenting as a reddish-brown with a white underbelly.
Though some may have spotted patterns, it is less common. They have giant mouths and sharp teeth that aid in catching their diet of sand dollars, shrimp, and mollusks.
Yellowtail flounders prefer the Atlantic coast, particularly the Chesapeake Bay and Cape Cod. Their broad bodies are half as wide as long and come in shades ranging from olive drab to dark brown.
In addition to their tail, the two long fins and underbelly are yellow. Yellowtail boasts splotchy, rust-colored spots that can be darker or lighter than their base color.
This feature is the reason behind their alternative name, rusty dab. Like the Gulf flounder, it is a vulnerable species because of overfishing.
Starry flounders live near Japan and the Aleutian Islands to Los Angeles Harbor. Like most flounder, this species can occupy both brackish and freshwater, so long as they are shallow. They are pretty large, weighing up to 20-pounds with lengths reaching 3-feet.
This flatfish is highly unique in that it can be right-eyed or left-eyed. They are technically categorized as right-eyed, though.
Starry flounders also have a patterning that sets them apart from most flounders, as their fins and tail are covered in thick, black stripes. Their name comes from their star-shaped scales.
With their strange, flat bodies, squashed appearance, and predatory diets, flounders are one of the more interesting marine species that occupy our oceans.
But despite their visual similarities, each has a distinct and crucial role in its ecosystem. Hopefully, this guide will help you identify what you have on your line the next time you head out in search of a flatfish dinner.