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why is my new hermit crab not moving?

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

Many stresses are put on new hermies during capture and transportation. The process of transitioning from a natural environment to your tank can cause lethargy, illness, and even death. Post-purchase stress (PPS) is a leading cause of death in newly acquired hermit crabs within the first few weeks to a new home.

Post-purchase stress (PPS) or post-purchase death syndrome is an umbrella term for hermit crabs’ stress reactions when entering a new habitat. Your hermit crab may experience extreme lethargy, limb loss, and loss of appetite. That’s paired with agitation, aggression, escape attempts, excessive hiding, or digging.

Being able to spot these problems gives you a chance to help your hermit crab de-stress. The best approach is to offer it an isolation tank (ISO tank). This will have humidity and temperature ranges set at the lower end of its needs, enabling it to slowly transition to its new home in privacy.

Hermit Crab Post-Purchase Stress Definition

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

A study in Scientific Reports showed that hermit crabs can experience anxiety as a result of stressful situations. For this reason, many owners argue that PPS is caused by emotional distress.

Some state that PPS or PPDS in hermit crabs is caused by their physiological inability to adapt to rapid environmental changes. For example, Animal Biology shows that terrestrial hermit crabs are sensitive to temperature changes.

Low temperatures, in particular, are dangerous. As such, many experts argue that temperature and humidity fluctuations can cause PPS in hermit crabs.

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

Hermit crabs with PPS can experience:

These behaviors and incidents can be signs of other issues with your hermit crabs’ health. You must isolate any hermit crabs if you have concerns. The cause may be a contagious issue.

New Hermit Crab Behavior

Why Is My New Hermit Crab Not Moving?

Hermit crabs are usually nocturnal creatures. That’s why you need to get a sense of their routine rather than making a quick judgment when your hermit crab isn’t moving. 

There could be several normal reasons why one of your hermit crabs is stationary for extended periods of time.


A hermit crab primarily sleeps during the day to avoid drying out during the day in the heat of its natural environment. A sleeping hermit will be found in an out-of-the-way section of its habitat, tucked inside its shell.

While sleeping, a hermit crab will keep its antenna close to the mouth of its shell to sense predators.

Humidity Levels

High levels of humidity or heat inside a hermie’s shell may cause it to sleep outside of that shell. If it does, you’ll find your hermit crab lying motionless somewhere in its tank.

However, a sleeping hermit crab will start to move if you pick it up. If your hermit crab doesn’t move when you pick it up, the humidity levels could be making it sick and, thus, motionless.  

Molting Exoskeleton

Molting involves a hermit crab shedding its old exoskeleton to grow. This is an energy-consuming process, which is why a hermit crab will be motionless throughout the duration.

It’ll often bury itself for protection during this time. Don’t move your hermit crab during molting as it’ll be fragile.


If your hermit crab is neither sleeping nor molting, it may have a health problem.

If your hermit crab is new, it’s likely struggling with post-purchase stress. Signs of illness, injury, or issues such as PPS can include various behavioral changes.

Why Is My New Hermit Crab Not Eating?

According to Zoological Studies, they have limited tolerance for cold, excessive heat, and other climatic extremes.

When faced with uncomfortable situations, hermit crabs may become lethargic and lose interest in eating. Figuring out whether a hermit crab has stopped eating can be tricky as hermies don’t eat large amounts when in good health.

If you’re concerned that your hermit crab isn’t eating, it may be eating at night. To check if this is the case, you can smooth the sand around its food and water sources. If the sand is still smooth in the morning, then the hermit crab is not eating. Of course, this works best when the hermit in question is isolated from its tank mates.

As well as post-purchase stress, hermit crabs can experience suppressed appetite due to illness or the natural and normal process of molting. If your hermit crab is molting, you may notice that it no longer moves as much.

Likewise, it may bury itself in the substrate so that it can molt safely and privately. Ideally, a hermit crab preparing to molt should be isolated to ensure minimal stress and disruption.

My New Hermit Crab Buried Itself

Perhaps you recently bought a new hermit crab and introduced it into the main habitat. Then, it buried itself and won’t come out. It could be dealing with PPS. Hiding, retreating into its shell, or burying itself are common signs.

There are other reasons as to why a hermit crab might bury itself. These include:


If your hermit crab is molting, it’ll stay buried for the duration of the process.

This can take between 1-2 months, so be patient and don’t move it during this process. Hermies are fragile during this time, and moving them could result in injury.


It’s easy to forget that hermit crabs are burrowing animals.

They create tunnels and burrows throughout the day. By burying itself in the tank, your hermit crab is enjoying itself and replicating the environment it would live naturally in.

Looking for Food

A more concerning possibility is that a hermit crab is repeatedly burrowing, tunneling, digging, or burying itself in search of food.

In the wild, hermit crabs dig to locate meals. In domesticity, digging in search of food could signify that your hermit crab is lacking key nutrients. Try mixing up the food that’s on offer to see if that rectifies the behavior.

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. In this case, you must assess the habitat.

Unfortunately, when mitigating PPS, it’s impossible to know exactly how a hermit crab was transported. As such, you must assume that a new hermie experienced a rough ride and needs to be gently introduced.

Contributing factors to the formation of PPS in hermit crabs usually include:

  • Extreme stress during capture and transportation
  • Suboptimal conditions in many pet stores

If the stress has been too prolonged, or the climatic changes between their original, transitional, and domestic environments are too big, a hermit crab could even die. Your best chance at preventing this is to slowly introduce the hermies to your main tank via an ISO tank.

How to Make An ISO Tank

Your isolation tank should have everything that the main habitat does. The difference will be in the actual climate of the isolation tank when compared to the main tank.

Your isolation tank should have:

  • Ample, varied food sources
  • Moist, properly mixed substrate – 3 times deeper than the size of the hermit crab
  • Water sources, fresh and salt
  • Toys for climbing
  • Hiding places

If you ensure that your isolation tank has these resources, a new hermit crab will have the best chance of de-stressing and acclimatizing.

When you first introduce a new hermit crab to your isolation tank, set the heat and humidity to the lower end of its needs. This means that if the previous environment was cold or dry, the change would not be too shocking.

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

When you do introduce it to the main tank, the environment will be less shocking. A happy, healthy hermit crab will be far better placed to fit in with its new tank mates.

A hermit crab with PPS will behave with lethargy, burying behavior, and aggression. It may stop eating and show signs of illness. By understanding what causes this behavior and how to ease the transition, you can help your hermit crab recover from post-purchase stress.