Harris' mud crab

Body contents

Harris' mud crab (Rhithropanopeus harrisii) competes with native species and can spread crustacean diseases. It can damage the catch in fishing nets and clog water intake pipes.

Harris' mud crab (Rhithropanopeus harrisii)
Rhithropanopeus harrisii juvenile

What to look for


  • greenish brown to olive green
  • white-tipped claws, unequal size
  • hairy abdomen
  • 4 spines on each side of body
  • slight notch between the eyes
  • eyes not at the widest point of the body
  • body about 1–2cm wide
  • often found in dense groups.

Where to look

Look on or around:

  • fishing nets
  • mud
  • rocks and stones
  • sand
  • vegetation and oysters
  • water intake pipes.

Likely habitats include:

  • salt, brackish or fresh water
  • shallow waters.


Similar native species

These native species look similar to Harris' mud crab. It does not need to be reported.

River swimming crab (Varuna litterata)

Missing media item.


  • red-brown body
  • body up to 5.5cm wide
  • claws are the same size
  • 3 spines on each side of body
  • flattened legs
  • legs covered with long hair on inside edge of last 2 segments.


  • can live in fresh or salt water
  • prefers sandy areas with high tidal flushing.


Report it

See something unusual? Report it. Even if you’re not sure.

If you see something you think is a pest:

  • note the exact location
  • take a photo (use something for size reference, like a coin or note)
  • contact your state or territory authority.


Stop the spread of marine pests

Start with these simple steps:

  • Inspect and clean your boat or yacht. Make sure you check hard to reach areas.
  • Treat the hull of your boat or yacht regularly.
  • Clean and dry your fishing and diving gear after every use.

How you can stop the spread of marine pests.

Your location

Check our marine pests map.

The map shows known pests and pests to look for around Australia.

Harris' mud crab (Rhithropanopeus harrisii)

Harris' mud crab (Rhithropanopeus harrisii)

Not established in Australia

Features: Greenish brown to olive green, with white-tipped claws of unequal size. Hairy abdomen. 4 spines on each side of body. Slight notch between eyes. Small (1-2cm). Often found in dense groups.
Habitat: Subtidal, estuaries and other brackish water.
Affects: Native species, fishing, water intakes.
Movement: Vessels, possibly fishing gear.