The flounder is a laterally compressed ocean-dwelling flatfish with both eyes (in adults) on the “top” of its body. In the case of southern flounder, the left side is always the upper side; in other species, the opposite is true. As an adult, a flounder camouflages itself as protection against predators. A small body cavity and the absence of air bladder aid in maintaining its position on the bottom. Small flounder grow rapidly and may reach 12 inches in length by the end of their first year. Males seldom exceed 12 inches, but females grow larger than males and often reach a length of 25 inches.
Adult southern flounder leave the bays during the fall for spawning in the Gulf of Mexico and spawn for the first time when two years old at depths of 50 to 100 feet. After eggs hatch, the larval fish swim in an upright position and the eyes are located on opposite sides of the head. The right eye begins to "migrate" to the left side of the head with aging. When body length of about one-half inch has been attained, the eye migration is complete and the fish assumes its left-side-up position for life. A flounder's diet consists mainly of fish spawn, crustaceans, polychaetes and small fish. Their width is about half their length.
Adult flounder normally inhabit shallow coastal and estuarine waters during the warmer months of the year and remain offshore during the colder months.
Flounder are found in coastal lagoons and estuaries of the Gulf of Mexico, Atlantic and Pacific Oceans.