Snail Identification

Header Image
Great blue heron eating a fish

Native Species

Native species: Physids

Physids

Key identifying features

  • Hold shell opening facing you with whorl pointing up, the shell opening should be on your left (i.e., left-handed shell).
  • Small, ranging from 2 to 8 mm in size
  • Conical in shape
  • Dark brown to green in color

Text and photo reference:
Johnson P. Quick and dirty guide to pond snails. Ecology and Evolutionary Biology, University of Colorado Boulder.

 

Native species: Lymnaeids

Lymnaeids

Key identifying features

  • Hold shell opening facing you with whorl pointing up, the shell opening should be on your right (i.e., right-handed shell).
  • Common in pond habitats.
  • Generally pale-yellowish to dark brown in color.
  • Spiraled or conical in shape.
  • Can be greater than 30 mm in size.

Text and photo references:
Johnson P. Quick and dirty guide to pond snails. Ecology and Evolutionary Biology, University of Colorado Boulder.

 

Invasive Species

 

Invasive species: New Zealand mudsnails

New Zealand Mud Snail Potamopyrgus antipodarum

Key identifying features

  • Hold shell opening facing out with whorl pointing up, the shell opening should be on your right (i.e., right-handed shell)
  • Adult snails are often over 3-5 mm in length in Western U.S.
  • Operculum (trap door) present
  • Usually 5-6 whorls
  • Color varies from gray, light to dark brown
  • Can be found in the water or on the banks

 

Chinese Mystery Snail Bellamya chinensis

Invasive species: Chinese Mystery Snail

Key identifying features

  • Hold shell opening facing you with whorl pointing up, the shell opening should be on your right (i.e., right-handed shell).
  • Adult snails are often over 5-cm in length, but can be smaller.
  • Operculum (trap door) present.
  • Typically light to dark olive green.
  • Top of whorl of shell may show chipping or weathering.
  • Uniform coloring on the shell.

For more information: USGS Chinese Mystery Snail Fact Sheet

 

Invasive Clams

 

Asian Clam Corbicula fluminea

Invasive species: Asian clams

Key identifying features

  • Clam size is 1 to 1.5 inches
  • Colors range from yellow-green to light brown or dark olive green to black.
  • Shell has concentric rings with weathering or chipping at tip.

Text and photo reference:
Foster, A.M., P. Fuller, A. Benson, S. Constant, D. Raikow, J. Larson, and A. Fusaro. 2012. Corbicula fluminea. USGS Nonindigenous Aquatic Species Database, Gainesville, FL.