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why is my new hermit crab not moving?

Post-Purchase Stress (PPS) And New Hermit Crab Behavior

Post-purchase stress in hermit crabs is an adverse reaction to being removed from the wild and everything that entails for a new life in captivity. This environmental change is stressful for hermit crabs.

The unwelcome transition leads to lethargy, burrowing activity, loss of appetite, and limb amputation.

Post-purchase stress (PPS) or post-purchase death syndrome (PPDS) is a leading cause of death in pet hermit crabs. PPS awareness means you can take action and assist hermit crabs with de-stressing.

A new pet hermit crab should enter an ISO tank before moving to the main tank.

Hermit Crab Post-Purchase Stress Definition

Post-purchase stress, or post-purchase death syndrome, covers a range of issues that a hermit crab may display when transitioning from one environment to another.

A study in Scientific Reports found that hermit crabs could experience anxiety due to stressful situations. For this reason, many experts argue that PPS is caused by emotional distress.

PPS in hermit crabs is due to their physiological inability to adapt to sudden environmental alterations. Animal Biology found that terrestrial hermit crabs are sensitive to temperature changes.

Whether PPS is caused by psychological stress or physical issues with environmental factors, it’s still extremely dangerous. Post-purchase stress can lead to serious illness and early mortality.

Hermit crabs with PPS can experience the following problems:

  • Not moving and remaining in one location.
  • Unresponsiveness.
  • Remaining burrowed.
  • Limb loss.
  • Appetite loss.
  • Agitation and aggression.

Attempts to hide in the substrate or escape captivity are common among newly acquired hermit crabs.

New Hermit Crab Behavior

Why Is My New Hermit Crab Not Moving?

Hermit crabs are nocturnal creatures, so you need to understand their routine rather than make a rash judgment about why they’re not moving. 

There could be normal reasons why one of your hermit crabs isn’t moving, including:


Hermit crabs sleep during the day to avoid predators and direct sun exposure. A sleeping hermit will be found in an out-of-the-way part of its enclosure inside its protective shell.

While sleeping, a hermit crab will keep its antennae close to the roof of its shell to detect predators.

Humidity Levels

High humidity inside a hermie’s shell can cause it to sleep externally to the shell. If that happens, you’ll find the hermit crab lying motionless in its tank.

A sleeping hermit crab will move if you pick it up. If a hermit crab doesn’t move when you lift it, the humidity levels could have made it sick and lethargic.  

Molting Exoskeleton

Molting involves a hermit crab shedding its old exoskeleton to regenerate and grow. It’s an energy-consuming process, meaning the hermit crab will be motionless.

It’ll often bury itself to feel safe, so never move a hermit crab when it’s molting.

Why Is My New Hermit Crab Not Eating?

According to Zoological Studies, hermit crabs have little extreme cold or heat tolerance. This is because they’re ectotherms, relying on their environment to maintain their body temperature.

When faced with unsuitable climatic conditions, hermit crabs become lethargic and lose interest in eating. If you never see a hermit crab eating, it may be doing so at night when you’re asleep.

If the food is untouched and the surrounding sand is smooth in the morning, the hermit crab isn’t eating. Of course, this simple test only works when it’s isolated from its tank mates.

As well as post-purchase stress, hermit crabs can experience suppressed appetite due to illness or molting. If a hermit crab is molting, it’ll seldom move until the process has been completed.

My New Hermit Crab Buried Itself

Perhaps you recently bought and introduced a new hermit crab to the main tank. Then, it buried itself and won’t come out. Hiding, retreating into its shell, or burying itself are common signs of PPS.

There are other reasons why a hermit crab might bury itself, including:


If a hermit crab is molting, it’ll stay buried because this triggers the molting hormone (MH).

The molting process takes 1-2 months, so be patient and don’t move it. Hermit crabs are more vulnerable than usual during this time, and moving them could result in stress or injury.


Hermit crabs are burrowing animals, creating tunnels and burrows for safety and enjoyment. A pet hermit crab will exhibit the same behavior in captivity as in the wild.

Looking for Food

An omnivorous hermit crab may burrow, tunnel, or bury itself to find plant and animal matter.

why is my new hermit crab not eating?

New Hermit Crab Not Moving – What to Do

Post-purchase stress is likely part of why your hermit crab has stopped moving or has taken to hiding.

It’s impossible to know how a hermit crab was captured and transported when mitigating PPS. Assume that a new hermit crab has had a difficult experience and must be handled sensitively.

Contributing factors to PPS in hermit crabs usually include:

  • Stress during capture and removal from its colony.
  • Being moved to a painted shell.
  • Difficult conditions during transportation.
  • Suboptimal conditions in shops and pet stores.

A hermit crab could die if the stress is prolonged or the climatic differences between their original, transitional, and domestic environments are too extreme.

Introduce the hermit crabs to the main tank via an ISO tank.

How To Make An ISO Tank

An isolation tank should have the same things as the main habitat, but the climate should differ. The isolation tank should have the following:

  • Abundant, varied food sources. Never offer the same food twice in 24 hours.
  • A moist, mixed substrate 3 times deeper than the size of the hermit crab.
  • Water sources, including freshwater and saltwater. Provide a ramp to get in and out.
  • The right lighting conditions, usually 8-12 hours of light and darkness. Use a timer.
  • Toys for climbing, as this is an important source of recreation.
  • Hiding places. Don’t attempt to get a hermit crab to come out or pick it up.

Set the temperature and humidity to the lower end of its needs before introducing a new hermit crab to the isolation tank. That way, the change won’t cause shock if its environment used to be cold or dry.

Over 3-4 weeks, gradually raise the temperature and humidity levels in the isolation tank until they match the main tank. This period of acclimatization will allow a hermit crab to rest and de-stress.

If you ensure the isolation tank has these resources, a new hermit crab will have the best chance of de-stressing and acclimatizing to its new life in captivity.

A hermit crab with post-purchase stress or post-purchase death syndrome may display lethargy, burying behavior, and hostility. Also, it may stop eating food, lose limbs, and show signs of illness.

Provide the right food and conditions while giving the hermit crab time and space to recover. The initial period in captivity will determine the likelihood of a new pet hermit crab surviving PPS.