• 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.