How to Identify a Summer Flounder (Paralichthys dentatus)

• Eyed side: A left-eyed flatfish — both eyes are on the left side of the body when viewed from above with the dorsal fin facing up.
• Body markings: The body has eyelike spots, with at least five of them arranged in an "X" pattern.
• Teeth in the mouth: Strong canine-like teeth.
• Tail shape: The tail fin is wedge-shaped, with the point in the middle.

The southern flounder may have 5 or more spots, but they are not eyelike; the summer flounder's spots are clear eyespots arranged in an X pattern.

The gulf flounder has only three prominent dark, eyelike spots forming a triangle (one on the lateral line, one above, one below); the summer flounder has at least five eyespots arranged in an X pattern.

Lives on or near the seafloor, often burrowing in sand, from nearshore to offshore sandy bottoms; juveniles also occur in estuarine marshes, seagrass beds, and open bays. Found in North America in the Atlantic Ocean from Nova Scotia to the east coast of Florida, not entering the Gulf of Mexico; concentrated mainly in the New England-Mid-Atlantic region.

Lay the fish flat on its side in even light and photograph the whole body first, then the details below. Spread the tail fin so its shape (forked, rounded or square) is clear. Get a close, sharp frame of the head: mouth, jaw length and any barbels. Shoot the side of the body before the fish dries; spots and stripes fade fast out of water. The app reads the photo and names the likely species; use the marks on this page to confirm it.

Size and daily limits for this species differ by state and by water, and some waters are catch-and-release only. Check the current regulations for where you are fishing before keeping any fish; if you are unsure of the species, release it.