Electric Blue Hermit Crab

With bright blue bands on its dark brown to black legs and orange antennae, the electric blue hermit crab is one of the most colorful hermit crabs. Like other hermit crabs, it lives in empty snail shells and changes shells as it grows. It contributes to the cleanup crew by feeding on algae, detritus and leftover food. However, the genus Calcinus is more inclined to kill live snails for their shells and to fight with other hermit crabs. Specimens in the trade are wild-collected.

• 60 liters or more; 2–3 spare empty shells with slightly wider openings for each crab.
• Salinity 1.023–1.026 specific gravity, pH 8.1–8.4, temperature 24–27°C.
• Reef-safe with caution: it hardly touches corals, but it may attack snails and knock over loose pieces.
• It should be acclimated by the drip method for at least 1 hour; copper-based medications are lethal.

Omnivorous; it eats algal film, short hair algae, detritus and leftover food. Giving sinking granules or pieces of nori 2–3 times a week makes it less likely to turn on snails.

Active and curious; it roams the rock surfaces all day. It may get into shell fights with members of its own species and other hermit crabs.

Good companions: clownfish, gobies, blennies, tangs; large shrimp such as cleaner and fire shrimp.

Avoid: valuable or few snails, other hermit crabs (if there are no spare shells); triggerfish, pufferfish, large wrasses.