Cusk Eel Identification Guide
Recognize cusk eels by their eel-like body and long fins that wrap continuously around the tail.
Read the full Cusk Eel encyclopedia entry →Key identification features
- Elongated, eel-like body tapering smoothly to a point
- Long dorsal and anal fins that merge continuously with the caudal fin, forming one unbroken fin margin
- No true pelvic fins on the belly; instead a pair of slender, filament-like jugular fins sits under the throat
- Smooth or finely scaled skin, often pale pink, tan, brown, or blackish
- Small eyes and sometimes chin barbels in deeper-living species
- Generally modest size, from a few centimeters to about a meter in larger species
Common look-alikes
- True eels: lack any pelvic fin remnant at all, while cusk eels retain thin throat-positioned jugular fins
- Hagfish: are jawless and finless, whereas cusk eels have true jaws, teeth, and paired fins
- Brotulas (close relatives): nearly identical in shape, distinguished mainly by bearing live young instead of laying eggs
Where you'll see one
Cusk eels occupy an enormous range of habitats, from shallow reef crevices and caves to the deepest ocean trenches on Earth, in temperate and tropical seas worldwide, usually staying near the bottom or hidden in dark refuges.
Frequently asked questions
How do I tell a cusk eel from a true eel?
Look under the throat: cusk eels have a pair of thin, filament-like jugular fins there, while true eels have no pelvic fins at all.
How can I recognize the tail of a cusk eel?
The dorsal and anal fins run continuously into the caudal fin with no separation, so the tail blends smoothly into the rest of the fin margin rather than forming a distinct fan.