Flatfish (Flounder and Sole)

Flatfish — Flounder and Sole: Nutrition, History and Cooking Guide

Flatfish — encompassing flounder, sole, plaice, dab, turbot, and halibut — share a remarkable anatomy: both eyes migrate to one side of the head during larval development, leaving the fish permanently tilted to swim and rest on the ocean floor with both eyes facing upward. The European plaice (Pleuronectes platessa), sole (Solea solea), and dab (Limanda limanda) are among the most commercially important flatfish in British and North European waters. Dover sole has been one of the most celebrated fish in French and British fine dining since at least the nineteenth century — its firm, sweet flesh suits the most refined preparations. Plaice — the most abundant British flatfish — is the traditional fish of seaside fish and chips in many coastal towns and was historically the most important flatfish in Britain by volume. Lemon sole, despite its name, is not a true sole but a variety of flounder.

Nutritional Value of Flatfish

Flatfish (flounder and sole species) provide 70 kcal and 12.4 g of protein per 100 g, with 1.9 g of fat — among the very leanest fish available. They provide complete protein, B12, niacin, B6, selenium, and phosphorus. Their very low fat content means omega-3 levels are modest compared to oily fish, though still present in useful amounts.

Health Benefits of Flatfish

Flatfish are one of the most calorie-efficient protein sources from any food — very high protein at very low caloric cost. They are suitable for virtually any dietary pattern and are recommended as a healthy protein by all major health bodies. B12 supports neurological health, and selenium supports thyroid function. As a low-fat white fish, they are an excellent protein choice for those managing weight, cholesterol, or fat intake.

How to Select and Store Flatfish

Look for flat, even fillets or whole fish with bright eyes, firm flesh, and a clean sea smell. The skin of plaice has distinctive orange spots on the dark upper side — these fade after death, so vibrant spots indicate freshness. Refrigerate for up to two days; freeze for up to three months.

How to Cook Flatfish

Flatfish are delicate and cook very quickly. For fillets: dust in seasoned flour and pan-fry in butter over medium heat for two to three minutes per side. For Dover sole meunière: whole sole is pan-fried in clarified butter and finished with lemon juice and parsley — one of the classic preparations of French cuisine. For plaice: grill for three to four minutes each side with a little butter. Flatfish suits the most delicate treatments — simple lemon butter sauces, capers, and fresh herbs — robust flavours overwhelm the subtle flesh.