Flounder (scientific family: Pleuronectidae), also known as flatfish, is a bottom-dwelling species widely distributed across the North Pacific, North Atlantic, and coastal waters of countries such as China, Japan, and Korea. Its most distinctive feature is its flattened body with both eyes located on the same side—usually the right—allowing it to lie flat on the ocean floor. Flounders typically inhabit sandy or muddy seabeds and feed on small crustaceans, shellfish, and benthic fish.

Flounders are moderate in size and known for their white, delicate flesh with a mild fat content and fresh, clean flavor. The meat is tender and subtly flavored, rich in high-quality protein and unsaturated fatty acids, making it a nutritious and premium seafood choice. In Japanese cuisine, flounder is especially popular and is commonly served as sashimi, sushi, salt-grilled, simmered dishes (nimono), or Kyoto-style miso-marinated (saikyo-yaki). Its light taste makes it ideal for showcasing the essence of “shun” (seasonality) and “mottenai” (minimalist purity) in traditional Japanese culinary philosophy.

High-quality flounder is often featured in banquet dishes or as a signature ingredient in high-end sushi restaurants. Additionally, some species of flounder are farmed through aquaculture and play a significant role in the global seafood industry due to their economic value and export potential.