Species Finder Species Posted Mar 14, 2000 Flounder Species Identification A flounder is a flatfish species that is made up of several different subspecies, based primarily on location. Common species include summer flounder, winter flounder, yellowtail, olive, and arrowtooth. Appearance Flounders are unique in that they have two eyes on one side of the head. The swim on their side completely flat against the bottom, and so both eyes can see what's above and all around. Their dorsal and ventral fin tend to run the length of its body. Colors vary depending on species.The width of the fish is generally half the length of the body. Maximum Size The olive flounder of Japan and northwest Pacific is the biggest flounder, reaching weights of over 30 pounds (13.6 kg). In North American waters, summer flounder reign supreme, weighing up to 23 pounds (10.4 kg) and growing to lengths of 36 inches (91.4 cm). Geographic Range Summer flounder swim in the Atlantic Ocean, with a range from Nova Scotia to the northern Gulf of Mexico. They are most common from Cape Cod, Massachusetts, to Cape Hatteras, North Carolina.Other species can be found throughout North Atlantic and Pacific Oceans. Habitat Flounders inhabit bays and estuaries, sticking right to the bottom for both feeding on prey and to hide from predators. Sandy gravel is the most common ground type that flounder look for. Food Types of foods depend on the flounder species. However, all are opportunistic hunters and will eat whatever comes across their path that's small enough, whether it be fish or crustacean. Predators For younger flounder, predators include spiny dogfish, goosefish (monkfish), cod, silver hake, red hake, spotted hake, sea raven, longhorn sculpin, and fourspot flounder. Predators for larger adult flounders include sharks and rays. Information courtesy of NOAA.