Silver Lamprey Identification Guide
Identify a Silver Lamprey by its single continuous dorsal fin and bright silvery sides.
Read the full Silver Lamprey encyclopedia entry →
Key identification features
- Moderate-sized, eel-like body, typically 30-40 cm as an adult
- A single, continuous dorsal fin running along the back rather than two separate fins, a hallmark of its genus
- Bright silvery to steel-gray sides contrasting with a darker gray-brown back
- Oral sucker disc with numerous small, mostly single-pointed (unicuspid) teeth
- Single nostril on top of the head, typical of lampreys
- Functional, well-developed feeding disc used to parasitize host fish
Common look-alikes
- Chestnut lamprey is very similar but shows a duller, chestnut-brown body and has bicuspid (two-pointed) inner lateral teeth rather than the silver lamprey's single-pointed teeth.
- Northern brook lamprey shares the single continuous dorsal fin but stays much smaller and has weak, degenerate, non-functional teeth.
Where you'll see one
Silver lamprey is native to large rivers, lakes, and connected waterways of central and eastern North America, particularly around the Great Lakes drainage, where it spends its adult life as a parasite of large-bodied fish before returning to gravel streams to spawn.
Frequently asked questions
How do I tell a Silver Lamprey from a Chestnut Lamprey?
Look at color and teeth: silver lamprey has brighter silvery sides and mostly single-pointed teeth, while chestnut lamprey is duller brown with some two-pointed inner teeth.
What fin feature identifies the genus of a Silver Lamprey?
A single, unbroken dorsal fin running the length of the back, rather than two separate dorsal fins, marks it as belonging to the same genus as chestnut and northern brook lampreys.