This post examines the various types of flatfish seen in markets, with the exception of halibut. These fish go by many different names depending upon locality and marketing but brill, dab, flounder, sole, tongue, turbot and plaice are all flatfish. They are found ocean wide, with hundreds of individual species and hybrids. Flounder, meaning “flatfish” comes into English from the Old Norse flydhra by way of French flondre. 

In Europe the common, or Dover sole (Solea solea), turbot (Scophthalmus maximus) and the European plaice (Pleuronectes platessa) are currently the most valuable flatfishes. Turbot is still an important, but increasingly expensive, food fish that is now farm-raised is several European countries. Of lesser importance, but common in fish markets is the European flounder (Platichthys flesus). The common dab (Limanda limanda) was once considered a trash fish, but is now harvested commercially and is being pushed by celebrity chefs as an alternative to the overfished stocks.

On the North American side of the Atlantic, the summer flounder or fluke (Paralichthys dentatus) is a very important commercial species that is known for its firm but mild white flesh. The winter flounder (Pseudopleuronectes americanus), also sold as blackback or lemon sole is another popular species. Witch flounder (Glyptocephalus cynoglossus), sold as grey sole or torbay sole, is a thin but very delicious species. Yellowtail flounder (Limanda ferruginea) is one of the species often branded simply as “flounder” and has thin, white flesh that is versatile to cook with.

Pacific species include the popular Petrale sole (Psetta jordani), Dover (Microstomus pacificus) and English (Parophrys vetulus) sole.Yellowfin sole (Limanda aspera), a small flounder from Alaska, has the largest flounder fishery by landings in the United States. None of these fish from American waters are actually sole, they are species of flounder that are marketed as various types of sole, mostly because they either look or taste somewhat like true sole. Other commercially available Pacific flounder include Pacific sanddab (Citharichthys sordidus), arrowtooth flounder (Atheresthes stomias), and California halibut (Paralichthys californicus).

Buying Flounder and Sole

Flounder is a common sight in fish markets and is sold fresh whole or in fillets as well as in frozen fillets. Flounder fillets should be fresh looking, never dried out or ragged and most have a white to off-white color. The fillets should be free of worms, which can be easily seen since flounder fillets are very thin. If you do find a worm in the fillet just remove it with tweezers. For frozen flounder take a good look at the fish and check the date on the package. The thin fillets can get freezer burned very easily, which ruins not just the taste of flounder but the texture as well.

Most of the flounders have similar tastes, but texture, color and thickness of the fish differ.Overall, it is easy to switch one out for the other which is why fish sellers play the name game with them. The various “soles” are testament to that. Even where I live, I see menus selling broiled sole, or fried sole sandwiches. Well, what kind of sole? Grey sole or lemon sole? Both of which are really flounder. I know this, but much of the buying public does not. Historically the market is very fickle when it comes to lesser-known species, but I feel in this age of sourcing your food, letting customers know it is locally caught grey sole is a better strategy. Besides, these fish all taste great, regardless of the name.

Historic Recipe

To Dresse Flounders or Playce with Garlick and Mustard  (1658)

Take Flounders very new, and cut all the Fins and Tailes, then take out the Guts and wipe them very clean, they must not be at all washt, then with your Knife scorch them on both sides very grosely; then take the Tops of Tyme and cut them very small, and take a little Salt, Mace, and Nutmeg, and mingle the Tyme and them together, and season the Flounders; then lay them on the Grid-iron and bast them with Oyle or Butter, let not the fire be too hot, when that side next the fire is brown; turn it, and when you turn it, bast it on both sides till you have broyl’d them brown, when they are enough make your sauce with Mustard two or three Spoonfull according to discretion, six Anchoves dissolved very well, about halfe a pound of butter drawn up with garlick, vinegar, or bruised garlick in other vinegar, rubb the bottome of your Dish with garlick. So put your sauce to them, and serve them, you may fry them if you please.