Janitor Hermit Crab

Introduction

The Janitor Hermit Crab is a small but highly efficient member of any marine cleanup crew. It’s appreciated by aquarists for its scavenging behavior, helping to control algae, detritus, and leftover food. This hardy and adaptable invertebrate is a reef-safe choice that contributes to a balanced and healthy marine ecosystem.

Scientific Name

Clibanarius spp. (commonly Clibanarius digueti)

Common Name

Janitor Hermit Crab

Water Quality and Temperature

• Temperature: 22°C – 28°C (72°F – 82°F)

• pH: 8.0 – 8.4

• Salinity: 1.023 – 1.025

• Water Quality: Stable and clean marine water; sensitive to copper and nitrates

Feeding

• Omnivorous scavenger

• Diet Includes:

  • Leftover fish food

  • Detritus

  • Algae (including hair algae)

  • Meat-based sinking pellets or tablets

• Will benefit from supplemental feeding in sparsely stocked tanks

Tank Mates

• Peaceful and reef-safe

• Compatible with most community saltwater fish and invertebrates

• Avoid aggressive fish or large predatory invertebrates that may prey on hermits

• Ensure plenty of empty shells to prevent fights with other hermits or snails

Substrates and Tank Decorations

• Prefers a sandy or mixed substrate for burrowing and mobility

• Live rock and reef structure for grazing and hiding

• Stable rocks to prevent toppling while climbing

Suitable Plants

• Safe for macroalgae and most marine plants

• Will not harm seagrasses or ornamental algae

Sexing

• Males have slightly larger right claws and longer antennae

• Difficult to distinguish sexes without close examination

Breeding

• Breeding is extremely rare in home aquariums

• Requires a planktonic larval stage in open water

• Reproduction typically only occurs in the wild

Maximum Size and Longevity

• Maximum Size: About 2.5 – 4 cm (1 – 1.5 inches)

• Lifespan: 2 – 4 years in captivity with proper care

General Information

Janitor Hermit Crabs are ideal for nano and reef tanks, where they help maintain cleanliness without harming corals or other tank mates. Their name stems from their constant work cleaning up detritus and algae, earning them a place in most marine cleanup crews.

A Fun Fact

When it outgrows its shell, the Janitor Hermit Crab will often “try on” several shells before selecting its new home—like browsing through real estate options!