Species description

Care, breeding and tankmates

Invertebrate profile

Diet

Herbivore

These crabs are invaluable omnivorous scavengers that spend their time grazing on various types of nuisance algae, including hair algae and cyanobacteria. They will also greedily consume detritus, uneaten fish food, and decaying organic matter. If natural food sources run low in the aquarium, their diet should be supplemented with dried seaweed and sinking pellets.

Ecological role

Scavenger

They are quintessential members of the reef clean-up crew, performing essential janitorial duties across the rockwork and substrate. By continuously grazing on algae and processing detritus, they prevent organic buildup and assist in maintaining overall water quality. Their foraging activities also subtly sift the top layers of sand, preventing stagnation.

Shock sensitivity

High

Hermit crabs are comparatively hardy, but they still require careful acclimation to new water chemistry and temperature. Drastic shifts in salinity are particularly dangerous and can interfere with their osmoregulation. A slow drip acclimation is the recommended standard practice to ensure long-term survival.

Calcium and minerals

Medium

Proper calcium, magnesium, and trace element levels are mandatory to facilitate a healthy molting process and allow their new exoskeleton to harden. Regular water changes with a high-quality reef salt mix usually provide sufficient elements for their needs. Without adequate calcium, their new shell remains soft, making them highly susceptible to predation.

Molting

Shell growth

When it is time to molt, the crab may temporarily leave its shell and hide within the live rock until its new exoskeleton is sufficiently hard. The shed exoskeleton strongly resembles a dead crab and is often mistaken as such by inexperienced aquarists. Ensure spare empty shells of various sizes are always available so they can upgrade safely post-molt.

Reproduction

Oviparous

Reproduction in the home aquarium is an extremely rare occurrence and generally unsuccessful. They release microscopic, free-swimming larvae into the water column, which are usually swiftly consumed by corals and fish. Successfully raising these larvae requires dedicated pelagic feeding regimens and isolated rearing systems.

Compatibility & tankmates

Reef safe with caution

They are exceptionally peaceful toward fish and corals, making them an ideal and safe addition to any reef aquarium clean-up crew. However, they may occasionally squabble with other hermit crabs over desirable empty shells if resources are scarce. They generally ignore snails, provided there are enough empty shells to prevent them from killing snails for their homes.