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Profile photo of Stacy

by Stacy

PPS (Post Purchase Stress) Minimizing the Impact

February 21, 2013 in Biology, Caresheets, General

written by Sue Latell March 8, 2006

I have belonged to the on-line crabbing community for a little over 3 years now. From day one there was discussion about the number of deaths immediately occurring after purchase. It evolved into a named syndrome: PPS. Many “unexplainable” deaths that occurred in the time-frame from newly acquired to first post molt death were labeled PPS. Time lines wavered (anywhere from one week-up to one year), and alarmingly glossed over (in my opinion) too many other potential causes. The interesting aspect about this subject is that for all the debate that occurred, and the viable, if not absolute reasons offered, not one person or group was willing to agree or offer what to do to minimize it. What is more alarming about this is my own willingness to allow it to continue, even though I understand what PPS is! I think I have been maintaining PPS as an excusable reason for me to have a death in my population. It is important to me to be, or at least appear to be competent in the care of our charges. So grudgingly I have to admit that my complacency in not wanting to clearly define and action PPS, is so that I have a contingent reason to remain blameless for their death. It has been and is treated like this big mystery that there is no obtainable solution to! Well I think it is time to recognize what PPS is, as I am pretty sure we have had the answers at hand for some time!

The purpose of this article is to define what we know PPS to be TODAY; as we can understand its cause and is supported by the knowledge we have documentation for. We can amend standard care practices at this minute. That said, this definition should and will be refined as our successes and information on crabs grows. This is a first step to taking rightful responsibility for this type of crab death. There is a somewhat tested solution to this (if at this point, only by me) that I hope will evolve into an observed and practiced tactic. Please also refer to the companion article: “Refining the Purpose for ISOLATION”, for further clarification.

What is PPS?

PPS is the result of a crab’s inability to physiologically adapt quickly enough from his natural circumstances (environment and habits) into a transitional one and then into a captive environment. The inability to adapt is invoked and influenced by the degree of and withholding of elements the crabs need to adjust to their environment.

This statement means that crabs suffer the most risk of physical stress induced death from the change in their environment (heat, humidity, range and associated resources) by being harvested, shipped and housed by the pet merchants. Resources in this context are water, salt water, food and shelter. Explicitly we need to recognize that the stress is not an “emotional” one, which we have to tendency to relate more easily to. It is physical and involves their ability or inability to forage (for food); have access to resources such as salt water, fresh water; an appropriate substrate and/or room to metabolize to their new environmental surroundings (heat and humidity)! So what factors influence the potential for PPS?

Hermit crabs have remarkable stamina and can tolerate the extremity of their environmental changes for a certain amount of time. They also have built in metabolic processes that assist them in adjusting to their immediate environment. These include hibernation and respiratory regulation. These processes function when fueled appropriately by diet. Because they involve digestion and chemical adjustment, they take longer time to come into effect. Therefore, a rapidly changing environment can short circuit these process mechanisms. Another process, not quite of the same class is osmotic regulation. As long as there is physical access to water, crabs are immediately able to implement procedures to control temperature. This process is mostly reliant on water. A guide to understanding the time frame these processes can take for crabs to implement involves their initial health, their size, and how fluctuant the extremes are in occurrences and interval. All of these things by their very nature are aberrant! For example, a healthy crab can slow down his processes to accommodate a drop in temperature with minimal impact for about 7 days (the rough estimate it takes for a medium sized crab to ingest and process his last meal, plus exhaust immediate reserves). A lower humidity can also be accommodated in similar fashion. Water access does play a significant roll in this control mechanism, as well as for an over hot/humid situation. So if there is a lack of a key resource (water), or if the temperature they are kept at changes rapidly, they may be unable to sustain equilibrium for extended periods of time, especially if the crabs are not fed adequately. This inability does not immediately kill them, but the longer the duration of these types of events accrue, the more they become life threatening. This also explains why a crab may resort to cannibalism to survive!

The hardest part about determining if your crab may succumb to PPS is in the KNOWING if these circumstances were applicable to your crab’s journey to you. Well I can say with some measure of certainty that they would have had to endure significant change over at LEAST a 21 day period. That said, from some of the stories I have read on our forums, that time frame is modest! At some point in the future I will provide a more detailed accounting of what our crabs can go through to get to our pet stores, but for now let’s just focus on PPS.

Here is the really difficult point about PPS, and due to its nature, is probably the main reason we have continued to seek “reasons” outside of our control for PPS. Our NEW CRAB introductory practices! We pride ourselves on establishing and sustaining our interpretation of an “ideal” living environment for our crabs. Temperature and humidity are kept and monitored (by gauge) at the optimum levels (but not always in ranges>>bad, very bad). We for the most part provide the best in foods and offer both types of waters. Provide for hiding, climbing, digging, lighting; what more could our crabs possibly need and want in these circumstances? Why do they still die? Because we in our infinite wisdom think we have provided crab heaven! Well we missed an obvious problem. Not only have some of us taken on the belief that if we provide the right conditions crabs will recover just by what we provide, we have also ignored that crabs have the ability to adjust to their environment when they haven’t already been taxed to very extreme limits. This includes going from BAD environments to GOOD ones! We do not factor in what they have endured before getting to us, and we are quite strict in getting them into good ones as soon as possible. It seems that it is difficult for us even to conceive that we may be pushing them past their endurance level by moving them from that “Crab in a Cup” or dreaded mall kiosk, to a good crabitat set up.

Well in large part we are! We need to graduate them to the ideal conditions so their bodies and processes can catch up. How long can that take? Up to a month, and that is just strictly going by their ability to physically accommodate the change. What fuels that? Food taken in over time, waters and familiarity they gain in their surroundings. Then there is the possibility that they need to molt. Let’s hope they don’t have to for that first 30 day period. In my experience, molters that were new to my tanks suffered the greatest proportion of death! Death resulted 80% more then, than at any other time in my entire 6 year run!! The second month was a bit better at 30% death ratio, but after that it has (at least for me) been less than a 3% chance (at a 50 headcount) after 60 days.

So what are we supposed to do to prevent PPS?

Well while I am tempted to say that a procedure will “cure” almost all potential for PPS, it would be untrue. Since we have absolutely no control over when a crab is collected, or how long it has taken him to be collected, or have the experience to be able to with precision estimate at what point on the PPS scale an individual crab may be at, we have to generalize a treatment. We also cannot accurately factor in how people interpret heat and humidity, healthy diet and other handling aspects involved in overall crab husbandry.

So for the time being, PPS would be best addressed with a method that first allows for close observation by handlers, and secondly accommodates the crab’s ability to adjust to his immediate environment. So what does it take for these conditions to be utilized and what specifically does this mean?

The most important principal is GRADUATION of environmental conditions. Based on an average, calculated by scientists while they studied components of a hermit crab’s anatomical processes, they noted that it can take up to 96 hours for a crab collected and sampled directly from his native habitat to adjust to a change in environment. This is once the crab reaches his physiological threshold whereby hormonal triggers begin to occur. The hormonal regulation is fueled mostly by the crab’s food resources, but it also can include other regulatory systems. This means that a crab requires time to reduce physical stress by being able to adjust to his immediate circumstance. The greater the change, the less potential a crab has to adjust successfully, and co-dependent to time is the resources available to the crab either internally (through reserves), or externally in the form of food and water. Scientists have calculated that there is the highest successful adjustment when environmental changes occur in 5-7% increments. This means if they are adjusting temperature or humidity, they use the existing conditions as the constant, and use the percentage as the increment for adjustment. So how do we apply that to our method of introduction? By this:

1. Observe and recognize that your crabs are mostly leaving poor humidity and heat conditions. (Usually too high/low heat, and too low humidity) Also, food resources have probably (but not always) been limited, thus making the crab’s system “sluggish” and slow to respond to the change. See if they have had water vs. a sponge; note the approximate heat and humidity conditions and think of them in comparative terms to the ideal. Then establish a threshold (minimum tolerance level), that will be your starting point for readjusting crabs to the acceptable ranges.

This is not an exact process, because as you can already see, there can be several variables. I will provide an example, and after that I am afraid it will remain for the time being a function of trial and error, until we have more data in respect to successful outcomes. We will be measuring this by people providing key data that will be stored in a database. Once we tabulate “samples”, the increased number of samples will provide more accurate standards that we can provide as procedure to future situations.

2. We must utilize ISOLATION in a separate tank, where the environmental factors of heat and humidity is not PRESET at the ideal conditions. I have been concerned lately in the shift of thinking regarding the necessity of Isolation as part of the procedure for introduction. Far more focus has been placed on ISO being utilized for MOLTING. What I find frustrating about this, is that it is NOT necessary to do so in most circumstances. For re-acclimatizing stressed hermit crabs, it is! Please read the companion article “Refining the Purpose for ISOLATION”.

This is the sector where in the past I had remained flexible in terms of the duration of time we keep new crabs in isolation. That was when I was looking at it strictly from the perspective of general health and potential for bugs. What I was remiss in communicating, is that I have always as a practice kept new crabs in ISO for at least a month. In fact, it was rare that I move one to the main tank earlier even though they showed no indication of stress or contamination. The other important aspect of my ISO tank is that it is NOT at the same range in heat and humidity as my main population tanks. This was not immediately intentional; it came about from not being used! Why heat and humidify an empty tank?

Many of you already know that I do not advocate removal of pre-molt or molting crabs to isolation. So really my ISO has really only served as the transitional tank for new crabs, or as the treatment tank for sick ones. I think that initially this is why I had fewer occurrences of PPS, without knowingly doing it. My ISO built up to the ideal and equivalent main crabitat conditions over the period of time I kept them in ISO. I did not see the relationship until I consulted Peter about overheating issues and about dropped limbs. This was in early 2004. Principally what I learned about dropped limbs is that it was due to a stress induced shock caused by an extreme environmental change (that aspect was speculated and communicated already) and was just confirmed. The new information was that by controlling the extremity of the change, we would allow the crab to metabolically adjust less stressfully. It was outlined to me that changes in humidity and temperature should be gradually increased in percentage and in time to assist the crab. Or, at the very least , recognizing WHAT the differences in the crab’s initial environment were and adjusting the new conditions in relation to IDEAL conditions. I have shared this several times, especially when it was clearly explained by the owner how poor the previous conditions were. Consider this rationale: Remember reading at least once a story relating how a crab was able to survive DIRE conditions for up to a year and survive, only to die within weeks of being introduced to a “perfect” environment? Wouldn’t it stand to reason that the crab evolved to adjusting to his conditions to subsist in his environment if it occurred over an interval of time that his body could adapt to? Then we basically eliminated that interval to reverse the process, thus resulting in death. I saw immediately why this could be possible. Now you may understand too why I have been harping on maintaining “ranges” of temperature and humidity. It is because it can maximize the crab’s ability to adjust!

3. We must set a starting point for environmental conditions. If your crab comes from a pet store that has for example a heat lamp, no cover, no water, chances are that the approximate existing humidity range is 50% or lower. ASK how long the crabs have been in the store tank. If it has been more than 2 days, you will need to start at the lowest level that crabs can tolerate. That is 60% (with access to water and food), and a maximum tank temperature of 72 degrees. You would keep that level for a period of 72 hours and then increase it by 10% to 66%, and maintain that level for 72 hours, repeating the process until you match your main tanks average humidity level. This would take roughly 2 weeks if your target range was 79%. During this time crabs will need food to support the hormonal adjustment necessary to acclimate. Give them the fighting chance by not immediately moving them into a more competitive environment with your existing and healthier crabs! By sticking new crabs into a main population without benefit of isolation during their adjustment, you are diminishing the new crab’s ability to recover by increasing the resource competition level.

Temperature is not as significant to worry about; crabs use osmotic processes to control that! So their only need there is access to ocean salt water. It is the hormonally, or more accurately, the metabolically related processes that helps a crab adjust to humidity, and for that they need fuel and the time to process it. In effect this is how to minimize PPS.

Why is this not a fool proof cure?

This is the question that has held me back for some time. I wanted a definitive answer as to why PPS happened. It wasn’t until I looked at it in components that it became clear that while we can significantly reduce PPS, there will be circumstances that cannot be overcome. The ones I understand the most are:

1). Damage to gills from prolonged dehydration –

This condition thankfully is not too common, surfactants that the crab regurgitates from his digestive tract in order to self hydrate his gills, ultimately will result in death. There is nothing we can do if the conditions he endured drive him to this point.

2). Starvation-

While this seems to be one of the things we can combat more readily, if it has endured for a prolonged period of time, we may not be able to reverse the effects. A crab requires constant energy to sustain his metabolic changes. He may not be able to produce the necessary hormones to transition into his new environment. What’s imminently worse about this condition is that it can result in death for a crab that needs to molt, and remains a potential for causing molt death more typically, but not exclusively (depending on the crabs size) for the first few months of ownership.

3). Our humidity and temperature control-

Okay, I am prepared to deal with the flack I will get for blaming owners who fail to recognize the importance of maintaining temperature and humidity ranges. But there it is! There is an inherent mistake created when we relate heat and humidity in absolute terms! When we reply to inquiries with a comment like “set your heat and humidity to 80/80 and you can’t go wrong”, well, we do! While 80/80 is within the tolerable ranges, it does not communicate that these settings are the higher end of the range, and that there is and should be other temperatures and humidity levels within the crabitat. I realize that this occurs more out of a convention of speech and is not meant to mislead people. The sad reality is that people (especially new crabbers) take these stated levels literally and they worry and painstakingly try to achieve this exact ratio. What worries me about this is that we need to recognize AND COMMUNICATE that a crabitat should have RANGES of heat and temperature. The people saying that 80/80 produces active healthy crabs are not totally wrong (I just hate the way it is expressed because it gets misconstrued)…it is the “Way” it is interpreted when we use such an explicit example. We cannot show that the loftier areas will be lower in humidity but higher in heat…just like the middle of the tank will be closer to the true 80/80…and that the lower regions will be even more skewed temperature wise over the UTH (if there is one), below the lamp etc…so how can we communicate these acceptable ranges without creating a pseudo class that people use really by convention of speech and lack of full understanding how humidity and temperature work? It gets into dangerous ground when we say “oh Straws like the humidity at 85%”…well many of us do not segregate our tanks by species…and an E or PP may overheat when a tank is that over saturated!

I feel this aspect contributes greatly to crab death in general, and not just from the PPS perspective. Though it is related in the sense that we diminish our crab’s ability to adjust by not providing differences that our crabs can utilize! They are in a tank people! There is no comparison to their natural habitat where there is wind and tidal influences, ground cover, and the fact that they can move to utilize these resources at their whim, and instinct! We NEED to provide for that! I trust my own experience in this, and I admit I have never had an “unexplained” death 6 months to 1 year after getting them. So rather blatantly, I don’t think it is acceptable to define PPS over such a broad time-frame! I have had a couple of puzzling deaths, and I attribute it more to me not providing them with the proper foods, or the proper balance of adequate diet, and maybe even possibly poisoning them, than the soon to be dispensed idea that it is PPS! We need to call a spade a spade, or we are in danger of remaining blissfully, and BLAMEFULLY ignorant of real issues that we could resolve! I am ashamed that until a short while ago, I was willing to ignore the significant realization that WE are a component of PPS. I trust the results I have had over the years, and have now filled in the reasons (started by dumb luck, and now more understood) due to valuable information I learned from reading and discussing with experts the physical processes our crabs are capable of. Now it is time to use the information and change our methods!

So what will the new time defined extent of PPS related deaths be?

For now, until we amass actual numbers, I think my model that I accrued when taking in adopted crabs, and purchased new crabs will be used (a total of 117 over 2 years). That means that potential PPS deaths will defined for at least 30 days from original ownership date up to and including the first molt. This will be conditioned by the fact that if a molt occurs after the first 60 days (being the highest risk for PPS related death), then the death may be more attributed to a lack within the owners environment, not necessarily PPS. The factors used to qualify these latent molts will be crab size and review of the owner’s food list and environmental conditions!


PPS is Death as a result of a crab being deprived of the conditions and resources he needs to adapt to changes in his environment. We are part of that change. We can minimize PPS death by practicing ISOLATION and a GRADUATED increase to ideal crabitat conditions over a period of time to offset the poor conditions crab harvesting can create. These changes should occur in stages that the crab’s physical processes can accommodate. We need first to acknowledge the crabs own capability to adjust, and synchronize the environmental adjustments to their metabolic time frame. Death of a crab should not be classified as PPS outside of the initial established time frame of adjustment (30 days), unless there is a molt occurring within a 60 day time frame. After 60days, a case by case assessment should be done, and evaluated based on the crab’s size, on the conditions he came from, and from the examination of existing diet and environmental factors (heat and humidity). While PPS will be definite within the 30 day period, that likelihood in classification diminishes as time increases.

Implementation Recommendations:

This definition will be amended by statistical evaluation, and new study material. I recommend review in the process be conducted in 90 days time and that a committee be established in evaluating collected data. A permanent template with fixed element names should be used to feed the database for this data collection category: PPS.

Concurrent to this study, an evaluation of the specific accepted time frame for PPS to be considered a cause should be presented to crab care communities by poll. It should be encouraged that members also support their choice with their personal reasoning. This will then be used to help the committee establish the recognized and formally accepted time interval for decreeing PPS as the cause of death.

More articles about PPS:

Technique for Adjusting PPS Crabs
Comparative Example for PPS Practices
Preventing Death in New Hermit Crabs


Profile photo of Stacy

by Stacy

Technique for Adjusting PPS Crabs – Method

February 21, 2013 in Biology

 written by Sue Latell March 8, 2006


PPS is Death as a result of a crab being deprived of the resources he needs to adapt metabolically to conditional changes in his environment (humidity/temperature). The inability to adapt is influenced by the duration of depravation, on what elements were withheld that the crabs need to adjust to their environment (Mainly proper food, water, and light), and on the environmental conditions themselves. Death of a crab should not be classified as PPS outside of the initial established time frame of adjustment (30 days).


PPS does not apply to every crab. However if food deprivation and inhospitable environmental conditions exist from where you purchased/adopted your crab, then you should employ the PPS technique for re-acclimatizing him. Please remember it is up to you to establish what the crabs pre-existing conditions were. In most situations it is likely that at least one, if not both of these conditions exist.

This method revolves around control of the crab’s environment. As such, it is necessary to isolate the PPS inductee. The goal is to provide the ideal conditions for your crab to be able to resume utilizing his physiological processes. Key factors are food, humidity and access to appropriate light. We have previously allowed our crabs to “de-stress” by burying for extended periods of time. With PPS crabs, in varying degrees, allowing this approach within the main tank is what kills them. The variance is what is hardest to measure, so really a method to combat PPS is really a generalized procedure that will work no matter what the degree of PPS is.



Set up factors establish what controlled variables you use when setting up the Isolation Tank. Trials have been conducted for the following tank sizes: 2.5 gallon, 10 gallon, 20 gallon. It is recommended at this time to stick with isolation units of this size.

The controlled variable essential for crabs to be able to adjust to their environment is humidity. This will be explained in more detail in the method section of this article. Heat is a minor player in establishing the right conditions at this point. Temperature should be at the minimum range (70 -75) this includes the day/night variance allowed within the stated ranges. Substrate is used as the control mechanism for humidity; again please see the method section for clarification. Food intake is essential, and more importantly foods that fuel metabolic changes are needed. Your new crabs must eat. In order for them to process/store food energy, they also need to have appropriate light. Light is what transforms the food into energy they use to metabolize.


Inevitably there will be a time that one of the crabs you acquire may need to molt. If they do, it will be a surface molt. If there is more than one crab in the tank, use the pop bottle method to prevent potential vulnerabilities. DO NOT move him. It is best for you to observe. The highest fatality in molt deaths is now, so there may be little you can do for him anyway. If he had the opportunity to eat just before, great! DO NOT deprive him of the 12hour light cycle either. If needed for some shelter, just drape some sort of plant along the outside of the bottle.


Behavior plays into this process on several levels. First, as noted earlier, when crabs are in metabolic duress they have a tendency to bury themselves. While this behavior is appropriate within the crab’s natural habitat when dealing with day to day environmental influences (extreme weather change, lack of ground cover during the day), it is not good to allow them to do so when they are suffering PPS. In order to overcome this, we must ensure that the tank we set up will not allow them to bury! This will keep them on the surface to “tank up” on the elements they need that will help their bodies to adjust again. So for most of the adjustment period we will keep the substrate at minimal depth. This behavior is also a tool we can use to monitor the crab’s progression. If he can’t dig and is stressed he will appear sluggish with little movement (on the surface where we can see it). Once he acclimates you will see him moving around freely which will indicate that he has adapted to the current conditions.

Another behavior we need to adhere to is their foraging behavior. At no time during this process should the same food be left in the tank on an overnight basis. If they eat everything in their dish, give them something new, but minimally! They, much better than we, know what they need. All we need do to accommodate them is have all food groups at their disposal! If possible allow for at least a 7 day lapse between feedings of the same foods. (A suggested menu will follow) Untouched food should remain in the tank for only 8 hours and then remove it. You may immediately replace it with new food (they may want it). The sooner your crabs eat, the more likely they will live! During the adjustment period if they do not eat, DO NOT accelerate to the next adjustment level humidity wise. Most energy expended in a crab is for adjustment to environment, it must be fueled by food!

The last behavioral aspect we must consider is topographical. Crabs really prefer to have a range with groundcover. Since we are eliminating the digging element, we can reduce stress by providing plant cover. Use of coconut huts or other hiding structures is really counterproductive in this process, so don’t use them. We want to be able to observe them throughout this process, and plants will accommodate this while still meeting the crab’s behavioral needs.


10 gallon glass tank w/ lid
Temperature and Humidity gauges
25 watt full spectrum bulb (clamp style preferred, but tube ok)
UTH (only if necessary to sustain minimum levels of heat range)
Plants for ground cover (silk or plastic) –grasses, vines, driftwood
DRY sand, enough to cover bottom of tank from 1/2 – 1” depth
Un-dyed reptile moss (moistened with ocean salt water mix, squeezed dry)
Fresh and Ocean salt water dishes
Food dishes
Appropriate shells to change into (at least 2 per crab)
Proper diet * see menu suggestions and Epicurean Hermit

Special note: Light must be 12 hours. How you choose to determine that cycle is up to you. If you


Scientists have calculated that there is the highest successful adjustment in crabs to their environment when environmental changes occur in 5-7% increments. For our purposes a 10% adjustment rate is easier to calculate, and we only have to factor a slightly longer interval before the next change. So for example 3-4 days for medium and small crabs, becomes 4- 5 days, and 5-6 days for larger crabs becomes 6-7 days between adjustments in humidity.

I will describe these as stages…in most cases I have tested or trialed personally, there is generally no more than 4. That said, I have not had the opportunity to try with a Large or Jumbo crab, or a Straw that requires the slightly higher range, so for those of you about to do so, no worries, if an additional stage is required, it will follow the same procedure as outlined here.

Stage 1:


Dry sand 3/4 of tank length up to 1” depth (depending on crab size) – use 1/2” with small crabs. Dampened moss, wrung out, not dripping, filling remaining 1/4 of tank to 1” depth (can be slightly more, but watch humidity levels). If your room temp is 72 degrees, no UTH is required. Use UTH as needed to achieve temperature range.

Starting Temp: 70 – 72, as high as 75 when light is on
Starting and sustained humidity for this stage: 68 – 72% (this is about 2% below normal low range)
12 hour light cycle (mine is set 7 am to 7 pm), if humidity is an issue, up to 5 hours of moon-glow (15 watt) is okay to utilize.

Note- if you maintain the depth averages for a 10 gallon tank, these indicated ranges should be achievable. You may have to vent during the night to keep humidity stable. Your room/household RH and temp may affect these ranges. Adjustments to increase should be done by adding a little moss. Gauges should be placed near bottom center of your tank.


Keep the sand as dry as you can. Condensation and wicking from the moss may be a problem, but is usually offset with the12 hour light cycle, so no real adjustment may be necessary as long as you stay narrowly within the humidity range specified for each stage. Moss may also have to be re-dampened, or added. It has been noted by several people that the crabs will tend to eat the moss too…this is good! This stage is most critical as it is the first. Your crab will show that he has the reserves to live if you see activity within the first 48 hours, especially eating. Don’t give up though if he does not appear to spruce up. Maintain this level for 4 -5 days. (6 -7 if larger crabs) If all your crabs have been eating and showing other signs of activity (crawling, climbing, in the water) within this time frame, you are good to go and advance to Stage 2. If for some reason you have at least one crab that has not shown signs of eating/moving, you should leave them all at that level for another day or two. This process should not be rushed…especially at this stage.

Stage 2:


Dry sand 2/3 of tank length up to 1” depth (depending on crab size) – use 1/2” with small crabs. Dampened moss, wrung out, not dripping, filling remaining 1/3 of tank to 1” depth (can be slightly more, but watch humidity levels). If your room temp is 72 degrees, no UTH is required. Use UTH as needed to achieve temperature range.

Starting Temp: 70 – 72, as high as 75 when light is on
Starting and sustained humidity for this stage: 70 – 74% (this is just hitting the lower accepted ranges)
12 hour light cycle, if humidity is an issue, up to 5 hours of moon-glow (15 watt) is okay to utilize.

Note: some people in humid belts regionally have experienced an issue with night humidity climbing past the threshold. Use of a moon-glow bulb at night has helped reduce this problem. You may have to play with the amount of moss you have in there. You know of course at any time that it falls below the target range, moss can be added.


Once again you sustain this range for a minimum of 4-5 days. Eating + Activity by all means advance to next level. If one lags, remain on hold, checking progress daily.

Stage 3:


Dry sand 2/3 of tank length up to 1” depth (depending on crab size) – use 1/2” with small crabs. Dampened moss, wrung out, not dripping, filling remaining 1/3 of tank to 1” depth (can be slightly more, but watch humidity levels). You can begin to add coconut fiber or allow the sand to dampen up a bit, or add moss to a 2” level. If your room temp is 72 degrees, no UTH is required. Use UTH as needed to achieve temperature range.

Starting Temp: 70 – 72, as high as 75 when light is on
Starting and sustained humidity for this stage: 74 – 78% (this is within normal range)
12 hour light cycle, if humidity is an issue, up to 5 hours of moon-glow (15 watt) is okay to utilize.

Note: some people in humid belts regionally have experienced an issue with night humidity climbing past the threshold. Use of a moon-glow bulb at night has helped reduce this problem. You may have to play with the amount of moss you have in there. You know of course at any time that it falls below the target range, moss can be added.


Once again you sustain this range for a minimum of 4-5 days. Eating + Activity by all means advance to next level. All my trials have used coconut fiber as the additive to dry sand. Only a little need be added. I generally added one cup to a 10 gallon, and 2 cups to the 20 gallon. Again it really depends on how your humidity levels out in your region. I have had to allow the moss remaining in the tank to dry out so that the humidity would stabilize.


In total, there really is about a 3 week adjustment frame. My personal view is that I prefer to allow my newer crabs time to beef up out of the mainstream competition of the main tank; leads to healthier crabs in my opinion, so I let them remain in ISO for at least 30 days. Bigger crabs need more time to adjust. All of them need a well balanced diet from day one, on that note…

Dietary requirements:

These are the food groups, and examples of what foods are found within the grouping. Please note that there is overlap in what group these foods represent.

Protein and lipids: this is for energy to grow, forage, reduce competition or minimize cannibalism which more frequently occurs in captivity.

Foods in this class are: meats, fish like silver sides, gold fish, clams, oyster; bone marrow (all meats including poultry), nut meats (many also fall in the omega fats group) salmon skin(including fat). Some vegetation like avocado meat (only) and bamboo stalks. (which also provide Cellulose, high energy)

Carotenoids, Zeaxanthin and cellulose: these foods are necessary to assist the crabs metabolic functions of calcium absorption, processing of minerals, and coloring an individual crab has (darkens pigments). It also improves the crab’s immune system and nervous system functionality.

Foods in this class are: tannin rich leaves, bark, cambium (inner branch skins) of plants like oak, maple, mangrove root, some perennial leaves; fresh fruits and vegetables that are orange, yellow, red or dark green (i.e. squash, sweet potatoes, carrots, natural corn, mango, blue berries, etc); many flower petals (dry), spinach, foliage, bean sprouts, seaweed: spirulina in particular, reptile moss (from pet store) etc.

Carbohydrates: these foods are quick energy foods that will help your crab by immediately fueling them but saving their “stored” reserves necessary for metabolic function.

Foods in this group include: grapes, apple, honey, wheat germ, oatmeal, dried fruit (raisins mostly due to Copper sulfate use in others), banana, pineapple, citrus pulp (inner membrane of skin considered cellulose).

Omega fats: this food group is very important and is totally missed in commercial food formulations unless they are frozen foods! These are necessary for nervous system, exo-skeletal health and processing of carotenoids and other minerals. If there are deficiencies in this group it is typically exhibited by molt death (where you are uncertain), a mildewy appearance to the exoskeleton (they look dehydrated), and they are not active!

Foods in this group overlap protein groups. They include: Coconut, walnut, whole fish (like a dead gold fish), fish skin, animal fat, olive oil, some grass seeds, seeds, peanut butter, etc. There are many of these suitable, some found in fresh flower petals like roses, sunflower, crab apple blossom, etc. Take a look at the edible plants list at Epicurean Hermit!

Calcium: it is considered superior to provide more than one natural form of calcium! Calcium of course is used mainly for growth of the exoskeleton. Calcium without the support of light and carotenoids will not be properly absorbed by the crab! The acceptable form for supplementation outside of natural forms is Calcium carbonate powder ONLY!

Foods containing calcium, will also provide some proteins as well; here are the main foods ideally used: freeze dried brine shrimp, meal worms, blood worms, krill (fresh, frozen or freeze dried), shrimp tails, sand dollars, powdered oyster shell, cuttle bone, broccoli heads, milk.

7 Day Metabolic Menu

Day 1:


Written by: Susan Latell

Copyright © by Coenobita.org All Right Reserved.
Originally Published on: 2006-03-08 http://coenobita.org

More articles about PPS:
PPS Minimizing the Impact
Comparative Example for PPS Practices
Preventing Death in New Hermit Crabs

Profile photo of Stacy

by Stacy

Preventing death in new hermit crabs

September 25, 2012 in Biology, Caresheets, General

One of the biggest concerns when buying hermit crabs is early death due to PPS or Post Purchase Stress. The term PPS has been used commonly for many, many years in the hermit crab community. PPS is blamed for unexplained deaths of new crabs. The physical stress occurs mostly PRIOR to your purchase and how many of your new crabs die unexpectedly relies on how much stress was inflicted prior to purchase. The act of harvesting and shipping hermit crabs is very stressful as the crabs are denied humidity, food, water and warmth for long periods prior to shipping and during shipping. They mostly arrive at pet stores dry, hungry, dehydrated and sometimes cold. The last crabs harvested before shipping will be less stressed and more likely to survive. Naturally the opposite holds true for the first crabs to be harvested. Often it takes a period of time for the stress and dehydration to catch up with them but it does and the hermit crab dies. Sometimes it’s a week, or a month but it could take longer. Gill damage from dry air (lack of humidity) can be a slow painful death for a hermit crab.

There are some ways to give your new pet hermit crab the best possible chance at survival. When you purchase new crabs, take note of the store conditions. If there are no gauges, do your best to guess the humidity. When you bring home a new hermit crab, place it in an isolation tank with the same humidity as the store. Use a tiny amount of moss if needed to create the proper humidity. The temperature should be at 72F and remain there. Place a very small amount of sand in the tank, not enough for the crabs to burrow in. Leave the crabs alone except to change food and water. This will allow the crab to relax, destress and get enough to eat and drink. It is very important that your crabs eat well during this time. Food fuels metabolism and this is how they will adjust to the tank settings as you change them. Once you have a consist starting humidity at or near that of the store, hold it there for four days. In four days, add some more moss to bring the humidity up 5%. Continue to increase in this manner until your ISO tank is the same humidity as your main tank. Between the 3rd and 4th week, add more sand so that the crabs can dig down if they want.

If you buy more than one crab, it is okay to place them in the same isolation tank together. It’s a good idea to bathe the hermit crabs before placing them in your main tank. Use plain dechlorinated water. This bath is not required but it seems to be helpful. There is no evidence that stresscoat is actually beneficial to hermit crabs, or harmful for that matter. It is up to you if you want to use it. This is a good way to check for parasites (mites) before placing the new crabs in the main tank. If the hermit crabs have mites (parasites) you will should keep them quarantined until the mites are gone.

Sue Latell of www.coenobita.org has put together two articles on reducing the impact of PPS in newly purchased crabs. Members of The Crab Street Journal helped conduct the trials on this method and did report a definite change in the death rate of newly purchased crabs. The two articles are linked to each other and also explain the importance of having lights for your crabitat. These are MUST READ articles because they cover a lot of important information.

Refining the Purpose of ISOLATION

PPS (Post Purchase Stress): Minimizing the Impact

This information is based on the exclusive research of Susan Latell, All Rights Reserved.

More articles about PPS:
PPS Minimizing the Impact
Technique for Adjusting PPS Crabs
Comparative Example for PPS Practices
Preventing Death in New Hermit Crabs