Life is stressful for captive hermit crabs. They’ve been taken far from their wild habitat, kept in unfamiliar conditions, and thrust into life as pets. This isn’t an easy transition, so most hermit crabs will struggle with this transition.
To avoid stress in new hermit crabs, don’t put them straight into a primary tank. Leave your hermit crabs in a smaller isolation tank for a while to destress. Offer limited substrate, food, and water and give them time to adjust. In the main tank, mimic the natural habitat of hermit crabs so that they feel at home.
Hermit crabs are easily stressed, and this condition can quickly become detrimental to their health. Left unaddressed, it can even be fatal. You must identify the warning signs that hermit crabs are stressed, what’s causing the problem, and how to address the source of their mental discomfort.
Do Hermit Crabs Get Stressed?
Stress is a fact of life for hermit crabs, especially when new to captivity. It’s called Post-Purchase Stress (PPS). If you don’t take the appropriate steps to protect hermit crabs from PPS, they may not survive for long in captivity.
Think about the journey your hermit crab has taken to your home. It would have started life roaming free on the beach with its friends as hermit crabs are social and live in large groups. It would then have been subjected to the following:
- Plucked from the beach by a gatherer and put in a bucket
- Housed in a tank with inadequate humidity and a suboptimal temperature
- Fed a diet that it has no control over
- Forced into a painted shell to aid aesthetic appeal
- Left to await sale or shipped off to a wholesaler
By the time hermit crabs reach their final destination, they’re cold, hungry, and dehydrated. Not surprisingly, your hermit crabs are stressed. Some are well on their way to ill health or death, so they must be allowed to destress.
How To Tell if Your Hermit Crab is Stressed
Hermit crabs show stress in several ways. The sooner you recognize stress in hermit crabs, the sooner you’ll be able to rectify it. Common warning signs that hermit crabs are stressed include:
- Shedding of limbs. One lost leg is a warning, but the loss of multiple legs is reason for concern
- Hiding constantly, whether within the shell or buried under the substrate
- Refusing to eat, drink, or bathe
- Unprovoked aggression, whether toward other tankmates or owners
- Constantly climbing tank walls, as though attempting to escape
Never ignore stress in hermit crabs. It may be commonplace, but that doesn’t make it OK. From the moment you decide to bring hermit crabs into your home, you must provide an appropriate quality of life.
Can Hermit Crabs Die from Stress?
Stress can kill hermit crabs. They do not experience heart failure or cardiac arrest due to stress. Instead, the impact of prolonged unhappiness causes other issues. This is why pet hermit crabs die within days or weeks of purchase.
Dehydration is common in stressed hermit crabs. A hermit crab that is constantly burrowed risks growing dehydrated. There is no way of knowing how dehydrated the animal was before it reached your home.
Stressed-out hermit crabs may starve to death. This could take up to two weeks, so it’s a deeply unpleasant way to go. Hermit crabs coping with severe stress are uncomfortable surfacing to feed.
This may also be a matter of inability to eat, not unwillingness. As discussed, hermit crabs that are stressed shed their legs. Ones that lose multiple limbs at once may be physically incapable of accessing food.
Hermit crabs experiencing stress also have slightly lower immunity than contented conspecifics. This is dangerous because there are so many hazards that face hermit crabs in captivity. For example, bacteria and mold will have a faster impact on tightly wound hermit crabs.
Stressed-out crustaceans are less likely to defend themselves in the face of provocation from tankmates. If a dominant hermit crab attempts to steal a shell, the weakened hermit crab may wearily resign itself to this fete.
How To Help A Stressed Hermit Crab
The easiest way to help a hermit crab that’s stressed is to leave it alone. Most hermit crabs that are new to captivity will initially burrow. This may take weeks. It is adjusting and wants to be left alone.
You can theoretically speed up the recovery process of PPS, though. Before moving your hermit crabs into what will become their primary enclosure, set up an isolation tank. Do not be fooled by the name. You should still keep hermit crabs together in there.
Ensure the isolation tank has sufficient humidity and is warm enough. Ordinarily, 80% humidity and a temperature of 80 degrees Fahrenheit are recommended. If possible, learn what conditions the hermit crabs were kept in previously. Imitate these for comforting familiarity.
Steadily increase the humidity by adding moss to the tank. This can be added to the substrate, which should be lower than usual. If you give stressed hermit crabs enough substrate to burrow under, they’ll do so. As discussed, this can present a risk.
Place just enough of a familiar substrate to help the hermit crabs feel at home. Add small, shallow water pools of bathing too. New hermit crabs may be covered in parasites. Over several weeks, gradually adjust the environment of the isolation tank.
Increase humidity, temperature, and the level of the substrate. Add deeper bathing pools. The intent is to replicate the conditions of the primary aquarium in the isolation tank. Eventually, you’ll be ready to move the hermit crabs into your main aquarium.
If you already have hermit crabs in the tank, this is usually a good thing. They will help the new arrivals settle. Just keep an eye out for bullying. If you spot this, return your new hermit crabs to the isolation tank.
Why is My Hermit Crab Stressed?
We have discussed the many reasons why hermit crabs can suffer from PPS. It is not only new hermit crabs that experience stress, though. Even resident hermit crabs can fall victim to stress and anxiety.
Hermit crabs require constant vigilance to ensure that they remain happy and healthy. Despite what you may have heard, these are not low-maintenance pets. Stress, and the corresponding dangers, are never far away for hermit crabs.
Let’s look at the reason why captive hermit crabs are likely to encounter stress. Refer back to our list of symptoms. If you spot these in your hermit crabs, you must identify the cause and resolve it.
Inappropriate Living Conditions
As suggested previously, the habitat of pet hermit crabs should mirror that of wild living conditions. Failure to do so will simply remind them of their captivity. This is not a natural state of being for hermit crabs.
This does not mean that all captive hermit crabs are miserable by default. Create the correct living arrangement so that your hermit crabs will be as happy they ever were in the wild. They’ll enjoy all the benefits without the environmental threats, such as predators.
That said, it is not always easy to maintain a perfect environment. You’ll need to work hard and observe your hermit crabs. At the first sign of disgruntlement, consider what is provoking unhappiness. This will reap the rewards for all concerned in the longer term.
Humidity and Temperature
Arguably the most important elements of a hermit crab habitat are humidity and temperature. These must mimic those that a hermit crab’s natural environment. An easy way to remember this is the 80/80 rule.
Get a hygrometer to measure humidity in a hermit crab enclosure. This should always be at 80%. This creates a moist environment that helps hermit crabs breathe. In a habitat with insufficient humidity, hermit crab gills dry out and they will slowly suffocate.
If your humidity drops below 80%, use a misting spray. Consider adding moss to the substrate too. If your hermit crabs like to live in dirt, consider using creature soil as your primary substrate. This contains moss as standard.
Aim for a temperature of 80 degrees Fahrenheit in a hermit crab enclosure. This is the upper echelons of temperature, but most hermit crabs enjoy it this way. If your hermit crabs appear stressed, reduce this temperature in small increments. Never dop below 72 degrees Fahrenheit.
Lack of Space
Conventional wisdom dictates that hermit crabs can live in a 10-gallon aquarium. This is true of one or two hermit crabs. The more you bring into a habitat, the more space they will need. Aim to provide five gallons of space for each hermit crab.
While hermit crabs sleep piled up together, they still like to explore their surroundings. What’s more, hermit crabs are territorial. The more space they have, the less likely they are to grow distressed and squabble.
Food and Water
Terrestrial hermit crabs cannot live underwater. They can only hold their breath for so long. Prolonged exposure to water will cause the hermit crabs to drown. Despite this, land hermit crabs do submerge in water at least once a day. This wets the gills and aids breathing.
This also acts as a bath for hermit crabs. As hermit crabs poop within their shells, daily bathing is essential. Provide two pools for hermit crabs, with ramps or climbing apparatus to aid entry and exit. One pool should contain saltwater and the other freshwater.
Do not use table salt for the former. Hermit crabs are poisoned by iodine. Pick up marine salt from an exotic pet store. Never use tap water for the freshwater pool, either. This contains chlorine and heavy metals that are toxic to hermit crabs. Stick with bottled water or invest in a water filter.
In addition to water, consider what you feed your hermit crabs. As natural scavengers, hermit crabs enjoy a varied diet. Marine Ecology confirms that hermit crabs eat anything they can get their claws on. Avoid feeding the same food twice in any 24 hours.
Even calm and collected hermit crabs need hiding places. This could be under the substrate or behind rocks and other obstacles. Despite being socially active, all hermit crabs need time to themselves on occasion.
Ensure that the substrate in a hermit crab enclosure is deep enough to burrow under. Six inches will usually be enough. You will likely find that your hermit crabs bury themselves to sleep or molt.
Smaller hiding places are also important. Even if this is just a plastic bottle, it provides some measure of privacy. Keep caps on these bottles. You do not want your hermit crabs to mistake such a vessel for a shell and get stuck inside.
Hermit crabs are surprisingly fussy about cleanliness in their habitat. Part of this is due to health. Growths of mold, fungi, or bacteria can be harmful to the health of hermit crabs.
Hermit crabs dislike squalor, though. These animals bathe regularly to keep clean and try to eat anything that clutters their enclosure. This means that you will need to clean a habitat regularly.
Perform daily spot cleaning. This must involve removing any droppings in the aquarium. Consider wiping down the walls, too. Conduct a more significant deep clean that renovates the habitat every three months.
Boredom and Loneliness
We have mentioned many times that hermit crabs are social and enjoy living in groups. The importance of this cannot be underestimated. As explained by Acta Ethologica, solitary hermit crabs experience greater stress and anxiety levels.
In addition to having company, hermit crabs also need stimulation in their habitat. Bored hermit crabs grow stressed. Climbing apparatus is a must. Hermit crabs are natural climbers. Provide netting and rocks to clamber over. This will keep hermit crabs amused for hours.
Lack of Shells
Shells are critical to the happiness and security of hermit crabs. A ‘naked’ hermit crab with no shell will be in significant distress. This means that you must always keep a range of shells available.
Volume is all-important to shell selection. When choosing spares, select shells that match those that your hermit crabs presently occupy.
Avoid painted shells. These contain paint, which is toxic. If the paint chips, the toxins can make hermit crabs sick. Wet paint can also cause hermit crabs to get stuck in their shell. Natural shells are still beautiful and aesthetically striking.
When you provide new shells, you will notice that your hermit crabs line up to try them on. This is natural. In the wild, a dominant hermit crab will the choice of a new shell. Once this is accepted or rejected, the remaining hermit crabs will trade shells among themselves.
Excessive or Inappropriate Handling
Hermit crabs can be taught to tolerate handling. Some will even welcome it. These are the exception rather than the rule, though. Most hermit crabs prefer to avoid interaction with humans. They are uncertain of your intentions.
Teach your hermit crabs that handling is not always a bad thing. Once your hermit crabs have destressed to an extent, handle them one at a time. The best way to coach handling in hermit crabs is:
- Wear gloves to protect yourself from possible pinches
- Stretch the palm of your non-dominant hand so that no loose skin is available
- Grip the hermit crab by the shell (never the legs) with your other hand
- Place the crab in your palm. Do not leave it dangling in midair
- Offer the hermit crab a small treat
- Return the hermit crab to its habitat
Sometimes you will have no choice but to handle hermit crabs. They will need to be rehomed to molt, destress, or during the cleaning of an aquarium. Avoid handling hermit crabs for recreation. This is no fun.
Disturbed when Molting
Hermit crabs molt regularly. Young hermit crabs, especially males, molt multiple times a year. This occurs when hermit crabs grow too large for their exoskeleton. The crabs shed completely and grow a new exoskeleton, usually while burrowed under the substrate.
Molting hermit crabs must be left alone during this process. As the hermit crab has no exoskeleton, it has no protection. This makes the animal anxious and nervous. Any attempts to handle the crab during this time will scare it witless.
Do not worry about food and water. Hermit crabs eat more ahead of molting to store fat. This may resemble a fat bubble on the exoskeleton. Molting hermit crabs eat their shed exoskeletons. They also store water in their shell for this eventuality.
If possible, move your hermit crab to the isolation tank while it molts. This is the one time that hermit crabs will appreciate being kept alone. With no rival hermit crabs around, it can molt in peace at its own pace.
Bullying and Aggression
Hermit crabs are mostly docile and friendly to each other. As we mentioned, hermit crabs are likelier to be stressed alone than in company. Just be aware of mismatched power dynamics between hermit crabs.
All hermit crab colonies have a dominant and submissive hierarchy, which is usually respected by all. However, sometimes a larger hermit crab will attack a smaller hermit crab.
Watch your hermit crabs interact. If many hermit crabs surround one tankmate, knocking against its shell, watch for a reaction. If the hermit crab in question hides in its shell, it is being bullied. Equally, if any hermit crab tries to pull another out of its shell, you should intervene at once.
Place the bullied hermit crab in the isolation tank to keep it safe. It will still need some company. Trial different tankmates until you find a combination that works best. Hermit crabs remember social dynamics, so being reunited with a bully will cause further stress.
Hermit crabs can experience sickness. This could be caused by toxins in the environment of the habitat. Common reasons for hermit crabs to grow unwell include:
- Fumes around the habitat, such as air fresheners or deodorants
- Toxins in paint chips from painted cells
- Bacteria and mold growing on walls and decorations
- Copper and chlorine from tap water
The above can be fatal for hermit crabs. Immediately remove a sick hermit crab from the habitat and rehome it in the isolation tank, away from toxins.
They have sturdy stomachs and rarely experience sickness from food. As per The Biological Bulletin, hermit crabs also learn quickly about harmful food consumption. They will avoid such sustenance in the future.
There are two primary causes of injury – conflict with other crabs or falling from a height.
Hermit crabs rarely aim to hurt each other in conflict. Sometimes an accident may occur, though. Equally, some hermit crabs are more vicious than others. A well-timed use of pincers may injure a leg, eye, or abdomen.
Falling is also a hazard for hermit crabs. As we mentioned, they love to climb. If the hermit crab loses grip, it can take quite the tumble. Some hermit crabs get stuck on their back, dazed by their descent.
Ensure that your enclosure has sufficient substrate to offer a soft landing. If handling your hermit crabs, or letting them roam, watch carefully. A hermit crab can run out of a hand or off the end of a table.
Wild hermit crabs enjoy symbiotic relationships with smaller species. For example, as per Molecular Phylogenetics and Evolution, wild crabs welcome sea anemones into their shell. These anemones share food with hermit crabs and protect them from predators.
Unfortunately, not symbiotic relationships are mutually beneficial. Mites can be the bane of hermit crabs. These small bugs are attracted to the humidity and food in a hermit crab enclosure. They quickly lay eggs and become a dominant force in the aquarium.
Mites will attach themselves to hermit crabs, usually the legs, eyes, and abdomen. Hermit crabs will attempt to rid themselves of infestation by bathing in saltwater. If this is ineffective, hermit crabs may willingly amputate their own legs.
The only way to deal with a mite infestation is a complete deep clean of the enclosure. Relocate your hermit crabs temporarily and clean everything – walls, floors, toys, and decorations. Replace the substrate, or at the very least, bake it in the oven.
Stress is a common issue for pets, and the need to destress is significant in hermit crabs. These are wild animals that are forced into captivity. Once they adjust, hermit crabs can live a full and happy life. You must take steps to ensure this transition to their new home goes smoothly.