A number of different species of flatfish or flounder are found in coastal and ocean waters along the entire Atlantic coast of the U.S. Three of the most common flounder species in the Northeast are the Winter or Blackback flounder, the Summer flounder or Fluke, and the Yellowtail flounder. Flounder is a lean white fish with firm, delicate flesh. All flounder species have a similar body shape, and both have eyes on one side of the head which allows the fish to rest on the ocean bottom and look upward. The side of the fish that has the eyes is generally pigmented with color variations from species to species and at different times of the year. The eyeless side of the fish is generally lighter to white in color.

Winter or blackback flounder primarily live in shallow coastal waters during the colder "winter" months of the year. During the summer, they migrate out of shallow water to deeper and cooler ocean waters, and they move back to shallow coastal waters when the water's temperature begins to drop again. Winter flounder are most abundant during the colder months of the year, and during their seasonal migration in the spring to cooler ocean waters and again in the fall as they move back to coastal waters. Large winter flounder are commonly referred to as "lemon sole" in many markets. The terms "sole" and "flounder" are often confused, and are really two biological classifications of flatfish.

Summer flounder or fluke have a migratory pattern opposite that of winter flounder. Fluke migrate offshore to ocean waters 200 to 500 feet deep during the colder winter months. During the warmer summer months they move inshore to shallow warmer waters. Fluke are commonly a favorite target for summer recreational fishermen who in recent years have caught more fluke than commercial fishermen. Fluke is most available in commercial markets during the summer and during its seasonal migrations. Fluke is one of the larger flounder species, and it is commonly used for sushi. "Because of the size and high quality of fluke caught here on Long Island, we have established a respectable business for sushi, both here in New York and in Japan," explained Bill Milligan, owner of Milligan Seafood Company in Southampton. "Much of the fluke larger than 4 pounds is used for sushi."

Other flounder species commonly found in New York markets but less frequently caught by recreational fishermen include the Yellowtail flounder and Sea dabs or American plaice. These flounder species are similar to the winter and summer flounder and can be easily substituted in most flounder recipes.

Flounder have historically been a staple of seafood lovers in New York for generations. They have a delicate flavor and a fine texture that most people enjoy. Flounder is very versatile in the kitchen and can be prepared by steaming, poaching, baking, broiling, frying or cooking in the microwave oven. Broiled flounder is light and healthy and no big fuss. Because of its mild taste and delicate texture most flounder recipes do not contain strong ingredients that would mask the fish's natural subtle flavor.