on March 23, 2012

Some hermit crabs have an unusual relationship with the sea anemone.


Hermit Crab

Some hermit crabs have an unusual relationship with the sea anemone. The sea anemone has stinging cells that sting or even kill those sea creatures that come into contact with it; however, the hermit crab can carry sea anemones on its shell. And even when the hermit crab changes shells, the sea anemone will often transfer to the new shell. This relationship works for the benefit of both creatures. The sea anemone eats the crab’s left-over food particles, and the hermit crab gains protection from predators, as well as some camouflage, from the sea anemone.


  • A hermit crab’s color varies from red to brown to purple. Some species also have stripes, dots, or other patterns.
  • A hermit crab has ten legs. The front two have claws on them, which the crab uses to walk. The rear pair of legs is used to grasp onto the crab’s shell.
  • The crab’s abdomen is uniquely twisted to fit snugly into its shell.

Fun Facts

  • As the hermit crab grows, it must leave its shell and find a larger one. It uses shells that have been abandoned by other sea creatures, hence its nickname, “robber crab.”
  • The hermit crab’s two eyes are located at the ends of short eyestalks.

CLASS: Malacostraca (crabs, krill, pill bugs, shrimp, and relatives)
ORDER: Decapoda (crabs, shrimp, and relatives)
FAMILY: Paguridae (marine hermit crabs)
GENUS/SPECIES: About 500 species in more than 30 genera

Size: Varies depending on species
Diet: Worms, plankton, organic debris
Habitat: Most waters worldwide

Aquarium Guide

With fun facts about more than 100 animals, this long-awaited Aquarium Guide includes beautiful pictures and reveals the incredible facts and design features that point to our amazing Creator. This handy size guide is excellent for school field trips and family trips to your favorite aquarium!

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