Summer Flounder Identification Guide
Identify summer flounder by its left-eyed orientation, large toothy mouth, and faint ringed eyespots on the body.
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Key identification features
- Left-eyed flatfish with an elongated, oval, somewhat pointed body
- Large mouth armed with sharp teeth, extending well back under the eye
- Faint ocellated (ring-like) spots, often five, arranged loosely across the brownish-grey mottled back
- Excellent color-matching ability, so background pattern can vary with the seabed
- Slightly concave tail margin and a moderately arched lateral line
- Adults commonly 30-60 cm, with larger individuals known as "doormats"
Common look-alikes
- Winter flounder – right-eyed (opposite side), with a smaller mouth and no eyespots.
- Southern flounder – overlaps in range but lacks the faint ocellated spots seen on summer flounder.
- Gulf flounder – shows three bold, distinct ocellated spots forming a clear triangle, unlike summer flounder's fainter, less organized spotting.
Where you'll see one
Summer flounder range along the US Atlantic coast from Maine to Florida, favoring continental shelf waters and estuaries. They move inshore into bays and sounds during warmer months and migrate offshore to deeper water as temperatures drop in fall and winter.
Frequently asked questions
How do I quickly separate summer flounder from winter flounder?
Check which side the eyes are on: summer flounder are left-eyed while winter flounder are right-eyed, an instant and reliable way to tell them apart.
How do I distinguish summer flounder from southern or Gulf flounder where ranges overlap?
Look closely at spotting: summer flounder shows faint, loosely arranged eyespots, southern flounder is largely plain, and Gulf flounder has three bold spots forming a distinct triangle.