Rex Sole Identification Guide
Spot a rex sole by its very slender elongated body, weak small mouth, and unusually large pectoral fin.
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Key identification features
- Right-eyed flatfish with a very slender, elongated body
- Small, weak mouth compared to its body length
- Notably large, elongated pectoral fin on the eyed side
- Uniform pale tan to light brown coloring with few or no bold markings
- Skin is smooth and only lightly slimy to the touch
- Typically 12 to 18 inches long
Common look-alikes
- Petrale sole has a deeper, more robust body and a pronounced arch in the lateral line, unlike rex sole's slim, straight profile.
- Dover sole has slimier skin and a shorter pectoral fin, lacking rex sole's elongated fin proportions.
- English sole is more compact overall with a smaller pectoral fin relative to body size.
Where you'll see one
Rex sole live on soft mud and sand bottoms of the deep continental shelf and slope of the North Pacific, ranging from California north to the Bering Sea, typically found in cold water well offshore rather than in shallow bays, often alongside other deepwater flatfish such as Dover sole and petrale sole.
Frequently asked questions
How do I tell rex sole from petrale sole?
Rex sole has a noticeably slimmer, more elongated body and a large pectoral fin, while petrale sole is deeper-bodied with a pronounced arch in its lateral line.
What fin feature stands out most on a rex sole?
Its pectoral fin on the eyed side is unusually large and elongated relative to body size, a trait more pronounced than in most other North Pacific soles.