American brook lamprey are long, snake-like fish. They do not have jaws, scales or paired fins. Both adults and larvae are dark in appearance. Larvae have a fleshy hood covering their filter-feeding mouth. Adults have round mouths with rows of teeth known as an oral disk. Both larvae and adults have eyes, but the eyes of larvae are only able to connect the change from light to dark whereas adults have fully functioning eyes.


Unlike the parasitic sea lamprey, American brook lamprey larvae are filter feeders that feed on organic matter and microscopic plants and animals. They bury themselves in the sandy bottoms of rivers and creeks and feed as the current brings food to them. They will also occasionally search for food along the bottom of the creek. They stop feeding after they transform into adults.


Larger fish such as northern pike and catfish may occasionally eat brook lamprey.

Did You Know?

  • Forty species of lamprey exist worldwide.
  • Lampreys have not changed dramatically in the past 250 million years.
  • Lampreys are good indicators of water quality as they are sensitive to changes in sedimentation and pollution.

Sources and Additional Information

Pennsylvania Fish and Boat Commission - Lampreys
Maryland Sea Grant - Backyard Ecology: Lamprey
Massachusetts Division of Fisheries & Wildlife - American Brook Lamprey
Connecticut Department of Energy and Environmental Protection - American Brook Lamprey