Decorator Crab Diet: What These Master Camouflagers Eat

Decorator crabs (superfamily Majoidea) are omnivorous opportunists. Their diet varies by species, habitat, and size, but commonly includes:

Primary Food Categories

• Sessile/encrusting invertebrates (for decoration & food):
  • Sponges (Porifera)
  • Hydroids, bryozoans, tunicates
  • Anemones, corals (soft)
  • Algae (red, green, brown)
• Mobile prey (scavenged/predated):
  • Polychaete worms
  • Amphipods, isopods
  • Small crustaceans (shrimp, crab juveniles)
  • Mollusks (small gastropods, bivalves)
  • Detritus, carrion

Feeding Behavior

• Nocturnal foragers: Emerge at night; use chelae to pluck/tear.
• Decoration = pantry: Attached organisms serve as camouflage and living larder—crab crops them over days.
• Size-dependent: Juveniles eat more algae/microfauna; adults tackle larger prey.

Ecological Role

Omnivore/scavenger linking benthic primary producers to higher predators (fish, octopus, birds). Decoration behavior also structures epibenthic communities.

Species examples: Camposcia retusa (sponge specialist), Libinia emarginata (generalist), Oregonia gracilis (hydroid/bryozoan preference).