Aquarium Livestock Pet Care Guides

Fiddler Crabs


Coastal Swamps and Beaches of the Atlantic Ocean

Average Size

1-2 inches


1-2 years


Scavengers mainly, they will feed mainly on meaty foods and sinking pellets, but will also pick algae off rocks and driftwood.


Generally peaceful, although larger individuals can catch smaller fish and males may fight each other.

Tank Environment

Most commonly found in mangrove swamps, fiddler crabs are best in brackish (slightly salty) water, but can be acclimated from fresh to salt water. Area must be provided for the crabs to climb out of the water. A half-filled or banked aquarium with dry land or driftwood is ideal.

Interesting Facts

  • Males are distinguishable from females by looking at the claws. Females have two small claws while males have one larger claw that they use for courtship and defense. The name "fiddler crab" comes from this claw - the crabs look like they are playing fiddles while waving their claws around!
  • Fiddler crabs, like all other crabs shed their skin! This molting occurs regularly as the crabs grow. They will literally crawl out of their skin, leaving behind the smaller shell. During this time the new shell is soft, making the crab more vulnerable to predation.
  • Fiddler crabs are important intertidal animals, living in marshes and estuaries along much of our coastlines. They are important food sources for many animals and can dig burrows in the mud up to 24 inches deep, aerating the swamp.
  • Related