Purple Hermit Crab

Purple Hermit Crab

Scientific name: Coenobita violascens
Common names: Purple Hermit Crab, Violet Hermit Crab
Adult size: Around 5–7 cm body length
Lifespan: Potentially 10+ years in suitable care

📏 Size

• Can grow considerably larger than many commonly sold hermit crabs.
• Provide plenty of room for climbing, exploring and moulting.

🏡 Housing

• Use a large, secure, well-ventilated enclosure with deep substrate.
• Provide at least 15–20 cm of substrate so the crab can completely bury itself to moult.
• Include cork bark, branches, hides and climbing areas.
• Keep multiple suitable spare shells available.

🌡️ Temperature

• 24–28°C during the day.
• Avoid temperatures below around 20°C for prolonged periods.
• Use thermostatically controlled heating where required.

💧 Humidity

• Maintain around 75–85% humidity.
• Good ventilation is still essential.
• A humid environment helps prevent dehydration and supports healthy moulting.

🥕 Food

• Omnivorous and should receive a varied diet.
• Offer quality hermit-crab foods alongside vegetables, fruit, leafy greens and suitable protein sources.
• Provide a reliable source of calcium such as cuttlebone.
• Remove uneaten fresh food regularly.

💧 Water

• Provide two water dishes:
  • Fresh, dechlorinated water.
  • Marine-strength saltwater made with an appropriate marine aquarium salt mix.
• Dishes should allow the crab to enter and exit safely.

🐚 Shedding

• Hermit crabs moult by burying themselves underground.
• A moult can take weeks or even longer.
• Never dig up or disturb a buried crab.
• Ensure deep, moist substrate is available at all times.

🤲 Handling

• Can be handled occasionally but should not be handled unnecessarily.
• They may pinch when frightened.
• Support the crab securely and never pull it from its shell.

❤️ Health

• Dehydration, poor humidity and inadequate calcium can cause serious problems.
• Watch for damaged limbs, unusual inactivity or problems with moulting.
• Provide suitable shells as the crab grows.

🧽 Cleaning

• Remove waste and spoiled food regularly.
• Keep both water dishes clean.
• Replace contaminated substrate while avoiding unnecessary disturbance of established moulting areas.

🏠 Before You Bring Your Crab Home

• Have the enclosure heated and humidity-stable before introduction.
• Prepare deep substrate, climbing structures, hides and spare shells.
• Have both fresh and saltwater available from day one.

⚠️ Important Bits

• Do not use painted or damaged shells.
• Never use ordinary table salt to make saltwater.
• Hermit crabs are social and are generally best kept with compatible individuals when the enclosure is large enough.
• A buried crab must never be disturbed during moulting.
• Despite their name, hermit crabs are not solitary animals and require a stimulating environment.