Hermit crabs are delicate creatures, and emergencies can happen. Whether your crab is acting strangely, injured, or has left its shell, knowing how to respond quickly and correctly can make the difference between life and death.
What It Means:
A hermit crab leaving its shell is a serious emergency. This can be caused by stress, illness, overheating, aggressive tankmates, or shell issues. A naked crab is vulnerable to dehydration and injury.
What to Do:
Separate the Crab – Move them to a warm, humid isolation container (use a ventilated plastic container with a moist paper towel).
Check the Shell – Look for sharp edges, bad odors, or obstructions that may have made the shell uncomfortable.
Offer a Shell Bath – Fill a small dish with lukewarm dechlorinated water and place them near it to encourage re-shelling.
Provide Shell Choices – Offer multiple shells of similar size and shape.
Keep Them Warm & Humid – Ensure the humidity is 80%+ and the temperature is stable.
What NOT to Do:
Never force them into a shell – They must move in on their own.
Don’t put them in water – They could drown if they are weak.
If your crab doesn’t return to a shell within 24 hours, the situation is critical. Try increasing humidity, offering more shells, and keeping them in a safe isolation area.
What It Means:
Hermit crabs may stay still for long periods if they are stressed, adjusting to a new home, or beginning to molt. However, if your crab isn’t responding at all, it may be molting or worse, deceased.
How to Tell If Your Crab is Dead or Molting:
Check for a Bad Smell – A rotting fish-like odor means the crab has passed away.
Look for Gentle Movements – Molting crabs may twitch slightly.
Leave It Alone for 24-48 Hours – Molting crabs need time to shed their exoskeleton.
If You Suspect Death:
Carefully check for movement with tweezers (don’t poke too hard).
If it smells bad, remove it from the tank immediately to prevent bacteria growth.
What It Means:
Molting usually happens underground, but sometimes crabs molting on the surface were unable to dig due to stress, lack of deep substrate, or improper humidity.
How to Protect a Surface Molter:
DO NOT Move Them! – Touching a molting crab can cause serious injury.
Isolate Them – Use a plastic bottle with air holes or a cut plastic container to create a protective barrier.
Increase Humidity – Keep levels above 80% to prevent dehydration.
Leave Exoskeleton Intact – The crab will eat its old exoskeleton to regain nutrients.
If tankmates are disturbing the molting crab, you may need to carefully move the other crabs to a temporary tank.
What It Means:
Limb loss can happen due to stress, bullying, bad conditions, or illness. Crabs can regrow their limbs after molting, but recovery takes time.
What to Do:
Check the Environment – Ensure the temperature, humidity, and water quality are ideal.
Separate If Necessary – If tankmates are aggressive, move the injured crab to an isolation area.
Feed High-Calcium Foods – Help them regrow their limb faster with cuttlebone, shrimp, eggshells, or leafy greens.
Keep Stress Low – Avoid unnecessary handling.
If a crab loses multiple limbs quickly, it may indicate a severe health issue or extreme stress. Check for signs of toxic substrate, fumes, or improper conditions.
Ideal Temperature: 75-85°F (24-29°C)
Ideal Humidity: 70-80%
Too Cold?
If temperatures drop below 70°F, crabs slow down, become inactive, and may die from cold stress.
Use a safe Under-Tank Heater (UTH) on the side of the tank, NOT the bottom.
Cover the tank partially with a towel or blanket to trap heat.
Too Hot?
If temperatures exceed 85°F, crabs can overheat and become dehydrated.
Move the tank to a cooler area (avoid direct sunlight).
Increase ventilation – Remove the lid temporarily if safe.
Add extra water dishes – Higher humidity can help cool the tank.
What It Means:
Hermit crabs are social, but they may fight over shells, territory, or stress. If you see crabs pinching, pulling, or flipping each other over, action is needed.
What to Do:
Offer More Shells – Lack of options can cause shell fights.
Check for a Bully – If one crab is aggressive, temporarily isolate them.
Ensure Plenty of Space – Overcrowding increases stress.
Never let a weak or naked crab stay with an aggressive crab – It could be fatal.
What It Means:
Sometimes a hermit crab gets wedged inside a shell if it’s too small, if something is stuck inside, or if it has died inside the shell.
What to Do:
Soak the Shell in Lukewarm Saltwater – This may encourage the crab to exit.
Offer Another Shell Nearby – They may switch if the fit is uncomfortable.
Gently Tap the Shell – A light tap might help them move.
Never Try to Force a Crab Out – This could injure or kill them.
If your hermit crab has passed away, you should:
Maks sure that the crab is dead and not surface molting as they can look similar
Carefully remove the body – If it’s inside a shell, use tweezers to gently extract it.
Bury the body – If you prefer, you can bury the crab in a safe outdoor area.
Boil or Clean the Shell – If you want to reuse the shell, boil it in saltwater for 10 minutes and dry it completely before putting it back in the tank.
Many emergencies happen due to poor conditions or stress. Keeping the habitat stable, safe, and enriched will prevent most problems before they happen.