Side by Side

Summer Flounder Paralichthys dentatus

Typical: 15–22 in, 1–4 lb

Quickest tell: With the dark side up and the dorsal fin away from you, the eyes sit on the LEFT and the mouth is large and toothy, the gape reaching past the eye, separating fluke from the smaller, right-eyed, tiny-mouthed winter flounder.

• left-eyed: both eyes on the left side when the dark (eyed) side faces up
• 5 prominent ocellated (dark-ringed) eyespots arranged in an X, plus smaller scattered spots
• large mouth, sharp teeth, gape reaching to or past the rear of the eye
• mottled brown eyed-side, plain white blind side
• broad oval body with a long continuous dorsal fin

Full Summer Flounder guide — season, gear and rules →

Winter Flounder Pseudopleuronectes americanus

Typical: 12–16 in, 1–2 lb

Quickest tell: Right-eyed with a tiny puckered mouth and no eye-spots separates winter flounder ('blackback') from the left-eyed, big-mouthed, spotted fluke.

• eyes on the RIGHT side when the dark side is up
• small mouth, lips barely reaching the front of the eye
• smooth reddish-to-dark brown upper side with no ocellated spots
• white blind side, often with a rosy tinge
• rounded, almost diamond body outline

Full Winter Flounder guide — season, gear and rules →

When Each Is Running July — current month highlighted

Where Summer Flounder and Winter Flounder Overlap

Both run in Northeast — that is where telling them apart actually matters.

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