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InvertebrateMarineIntermediate

Hairy Hermit Crab

Aniculus aniculus

A large and structurally robust marine hermit crab, famously adorned with a bright red body entirely covered in a dense coat of golden sensory bristles.

Taxonomy

Class:Malacostraca

Order:Decapoda

Family:Diogenidae

Genus:Aniculus

Species:Aniculus aniculus

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Water Temperature

22 - 28 °C

pH Value

8.1 - 8.4

Water type

Marine

Invertebrate type

Hermit crab

Adult size

10 cm

Minimum group

>= 1

8 - 12 dKH

Ecological role

Scavenger

Species description

Geographical Origin and Habitat: Widely distributed in the tropical Indo-Pacific, from the Red Sea and East Africa to Hawaii and Polynesia. Inhabits shallow outer reef slopes and sandy lagoons. They inhabit shallow reef flats and rocky shores where wave action provides high oxygenation.

Taxonomy: Member of the family Diogenidae. A large hermit crab species reaching up to 8-10 cm in total length. Legs and claws are massive, covered in dense bristles. Grows to 8-10 cm. Their body is covered with dense, red sensory hairs that assist them in detecting water movements.

Social Behavior: Highly active, strong, and destructive. Capable of knocking over unsecured rockwork or corals. Shows a territorial and somewhat aggressive temperament compared to dwarf species. They show an active and curious behavior, constantly moving rocks and exploring the aquarium substrate.

Coloration and Sexual Dimorphism: Bright red or reddish-orange body coloration. Covered in prominent, dense golden-brown sensory bristles. Eyes are dark on red-and-white striped stalks. No visible sexual dimorphism. Size is the primary difference between genders, with mature males usually being larger than females.

Care, breeding and tankmates

Tank Setup: Requires a large tank of 40-50 gallons or more. Rockwork must be very stable and secure. Provide a deep sandy substrate and plenty of open walking space. Provide a deep sand bed and plenty of rocks to crawl on, along with extra shells for growth.

Diet and Feeding: Voracious omnivore. Consumes frozen mysis, krill, chopped mussels, clams, and fresh fish chunks. Readily accepts large sinking pellets and seaweed sheets. They are excellent scavengers that consume leftover foods, decaying matter, and nuisance algae.

Water Quality: Reef parameters. Salinity SG 1.021-1.025, pH 8.1-8.4, temperature 22-28°C. Highly sensitive to copper treatments and elevated nitrates. Keep water chemistry stable, ensuring calcium and magnesium levels are sufficient for shell development.

Compatibility and Tankmates: Not reef-safe with small invertebrates. May prey on large live snails, starfish, and small sleeping fish. Keep only with large, robust fish. Use caution when keeping them with delicate corals, as their climbing activity can cause damage.

Aquarium Breeding: Microscopic larval stages are pelagic and complex, and do not survive standard home aquarium filtration systems. Mating is rarely successful in home tanks due to the difficulty of raising the planktonic larvae.

Risks and Diseases: Low iodine or calcium leading to failed molts. Lack of suitable large replacement shells (e.g. Turbo or Conus) causes high stress. Avoid any copper-based medications in the tank, as copper is highly toxic to all hermit crabs.

Geographic Origin and Distribution

Widely distributed in the tropical Indo-Pacific, from the Red Sea and East Africa to Hawaii and Polynesia. Inhabits shallow outer reef slopes and sandy lagoons. They inhabit shallow reef flats and rocky shores where wave action provides high oxygenation.

Origin

Tropical oceans and reefsAfrica and Madagascar

Invertebrate profile

Diet: Omnivore
Ecological role: Scavenger
Shock sensitivity: Medium
Calcium and minerals: Medium
Molting: Yes
Reproduction: Bubble nest builder
Compatibility & tankmates: Species only

Image gallery

Licensed images linked to the species or, when marked, to the closest representative taxon.

Related species

Recommendations grouped by close relatives, companion choices, and similar care.

Variants and close relatives

Same atlas type, nearby scientific identity, genus, or family.

Hairy yellow hermit crab

Aniculus maximus

Species description

Care, breeding and tankmates

Geographic Origin and Distribution

Origin

Invertebrate profile

Image gallery

Related species

Variants and close relatives

Hairy yellow hermit crab

Ambon Hermit Crab

Blue-eyed Hermit Crab

Blueish Hermit Crab

Carnifex Hermit Crab

Dwarf Zebra Hermit Crab

Eurysternus Hermit Crab

Hidden Hermit Crab

Lined Hermit Crab

Orange-banded hermit crab

Red-stripe hermit crab

Snellius's hermit crab

Stebbing's Hermit Crab

Tricolor Hermit Crab

White hermit crab

Yellow-tipped Hermit Crab

Recommended companions

Grape caulerpa

Tailspot blenny

Caulerpa prolifera

Chaetomorpha macroalgae

Dead man fingers algae

Halimeda macroalgae

Red gracilaria

Beautiful Blenny

Blue assessor

Caulerpa taxifolia

Peacock tail algae

Red grape algae

Sea lettuce

Allen's blenny

Ambon Chromis

Axelrod's blenny

Similar care

Zebra Hermit Crab

Cook's hermit crab

Arethusa Hermit Crab

Boschma's hermit crab

De Man's Hermit Crab

Rosewater's Hermit Crab

Large Mediterranean Hermit Crab

Anemone hermit crab

Antillean hermit crab

Danai's hermit crab

Double-striped hermit crab

Pacific Hermit Crab

Striped-leg hermit crab

White-fingered Hermit Crab

West African hermit crab

Olive hermit crab