American slipper limpet (Crepidula fornicata)

Key features

  • Large internal aperture with a shelf extending half its length
  • Oval shaped, smooth shell
  • Irregular growth lines
  • Commonly found in stacks
  • Shell colour white, yellow or pink with red/brown streaks
  • Up to 5 cm long


  • Intertidal
  • Shallow estuaries & coastal bays
  • Mostly found on other shells or hard substrates in muddy areas, also found on sand, gravel & rocks


  • Competes with natives for food & space
  • Impacts commercial oyster beds

Known locations

  • Not yet in Australia

What you can do

  • Inspect & clean niche areas & antifoul your vessel regularly
  • Clean & dry equipment before transporting & using in a different location

Learn more

Read the national biofouling management guidelines for your sector.

Report immediately Outside known locations!

  • Note the exact locations
  • If possible, collect a sample and freeze in a plastic bag or take a photo
  • See for your state contacts

Report a sighting 

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