Post Purchase Death Reduction Method

This is a (hopefully) more simplified revision of the original. I have also created a printable calendar for tracking that is free to download.

Introduction:

The objective of this method is to reduce the impact of physical stress by keeping the hermit crab above ground eating well and exposed to light. Both are vital to the hermit crab’s ability to recover. This is a thirty day method. While this can be accomplished in three weeks, there is no reason to rush. If you are adding new (wild caught) hermit crabs to your existing colony it is important that you do not introduce sick or contagious animals to your healthy colony. Thirty days of observation and quarantine will prevent total colony loss.

Why should I do this?

Do you want your hermit crab to live? With proper care they can live at least 40 years in captivity. Most die within a year. Using this adjustment method to help the crab recover from the damage done will improve it’s chances of long term survival.

This method is for wild caught hermit crabs only, hermit crabs coming from poor living conditions at a store or with a previous owner. Captive-bred hermit crabs do not need the PPDRM. In fact, it will likely cause more harm than good. Captive-bred hermit crabs are born in and raised in perfect conditions. They are free of disease or parasites. They are shipped correctly. Do not apply the PPDRM to captive-bred hermit crabs.

Notes:

When planning your trip to purchase your new pets, take note of the temperature and humidity in the store crabitat. If there are no gauges or conditions are unknown we will use a standard starting point.

If these will be your first hermit crabs you can perform this method in the large tank that will be their permanent home.

Each week you will improve the conditions in the isolation crabitat so long as the crab is eating and active.

Normal food may seem foreign after a long time on pellets. Appetite can be stimulated at the beginning by offering greensand and worm castings. Both are highly nutritious and well liked. You can also purchase a special healing mix for hermit crabs from Mary Akers of Hermit House.

After the first 48 hours there should be some sign of improvement but if not, do not give up.

If you are treating for parasitic mites AND are forced to make one pool larger than the other, make the ocean water the biggest pool.

Supplies:

Glass tank with a lid (small tanks are harder to regulate but a 10 gallon is fine)
Thermostat to regulate the heat pad
Heat pad (insulation may be needed)
Fake plants, logs to climb
Thin layer of dry sand
Moss
EE or shredded coconut husk
Fresh and Salt water pools (Treated with Prime)
Overhead light (non heat emitting) 12 hours on/off
Digital gauges- must be calibrated
Spare shells
2 liter bottle cut in half in case of a surface molt

Do not make the sand deep enough to encourage digging, this can trigger a surface molt.

Do not provide cocohuts or hides, we need the crabs active and where we can see them. Plant cover and climbing toys are fine.

Feeding routine:

Stick to small portions.

Change food every day, never leave the day before’s food in the tank with the new food.

Do not feed the same food twice in a seven day period.

Food that is untouched after 8 hours should be removed and replaced with something new.

What to feed:

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, 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.

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, cuttlebone, broccoli heads, milk.

How often do I feed from each group?

Protein – everyday

Fruits/Vegetables – 6 out of 7 days

Calcium – 4 out of 7 days

Fats – 3 out of 7 days

Other – 2 out of 7 days

Stage 1

Environment:

Gauges should be placed near bottom center of your tank.
Dry sand up to 1” depth (depending on crab size) – use 1/2” with small crabs. Sprinkle in a small amount of eco earth. They should not be able to burrow.
Dampened moss, wrung out, not dripping to 1” depth (can be slightly more, but watch humidity levels).
Temperature should be 72F. Use a standard heat pad.
Humidity 70% (+/-2%) (Vent at night if needed)
12 hour light cycle
Fresh water- space will be tight in a 10 gallon tank but provide the best dish you are able to fit.
Ocean water-space will be tight in a 10 gallon tank but provide the best dish you are able to fit.
Decorative plants for cover but no hides. (We want to encourage the crabs to forage and eat.)

General:

This stage is most critical as it is the first. If the crab is lethargic ideally you will see increased activity within the first 48 hours, especially eating. Maintain this level for 5-7 days depending on how well the crab(s) are eating. Eating well at day 5? Move on to stage two. Weak appetite still? Wait two more days. 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. During the first week home, most hermit crabs dig down and die. The shallow sand is meant to prevent the crab from digging down and instead encourage it to eat so that it’s body can recover and adjust to the new environment. A surface molt may still occur. In that case, use the 2 liter bottle or other container to protect the surface molter from the other hermit crabs. If the hermit crab is in isolation alone, do nothing and continue through the stages.

Stage 2

Environment:

Gauges should be placed near bottom center of your tank.
Dry sand up to 1” depth (depending on crab size) – use 1/2” with small crabs. Sprinkle in a small amount of eco earth. They should not be able to burrow. Do not add substrate, just maintain beginning depth.
Dampened moss, wrung out, not dripping to 1” depth (can be slightly more, but watch humidity levels).
Temperature should be 74F. Use a standard heat pad.
Humidity 72% (+/-2%) (Vent at night if needed)
12 hour light cycle
Fresh water- space will be tight in a 10 gallon tank but provide the best dish you are able to fit.
Ocean water-space will be tight in a 10 gallon tank but provide the best dish you are able to fit.
Decorative plants for cover but no hides. (We want to encourage the crabs to forage and eat.)

General:

Maintain this level for 5-7 days depending on how well the crab(s) are eating. Eating well at day 5? Move on to stage two. Weak appetite still? Wait two more days. 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.

Stage 3

Environment:

Gauges should be placed near bottom center of your tank.
Dry sand up to 1” depth (depending on crab size) – use 1/2” with small crabs. Sprinkle in a small amount of eco earth. They should not be able to burrow. Do not add substrate, just maintain beginning depth.
Dampened moss, wrung out, not dripping to 1” depth (can be slightly more, but watch humidity levels).
Temperature should be 76F. Use a standard heat pad.
Humidity 74% (+/-2%) (Vent at night if needed)
12 hour light cycle
Fresh water- space will be tight in a 10 gallon tank but provide the best dish you are able to fit.
Ocean water-space will be tight in a 10 gallon tank but provide the best dish you are able to fit.
Decorative plants for cover but no hides. (We want to encourage the crabs to forage and eat.)

General:

Maintain this level for 5-7 days. At the end of the 7 days you can transition your hermit crabs to the main crabitat. If you choose to leave the crabs in isolation for one more week that is acceptable as well.

My personal recommendation is that you proceed to stage 4. The expectation is that if your new hermit crabs need to molt, they will dig down during this week. Risk of death during this first molt is high. If the hermit crab is in the isolation tank and digs down and dies it will be less of an issue than if it happens in the main crabitat. Stage four is written with this premise in mind.

Stage 4 (optional)

Environment:

Gauges should be placed near bottom center of your tank.
Sand to half fill the crabitat. Should be just damp enough to hold it’s shape when your poke your finger into the sand. Mix this sand 5 parts to 1 part eco earth (dry).
Dampened moss, wrung out.
Temperature should be 76-80F. Use a standard heat pad. It will be challenging to maintain a cooler zone in a 10 gallon tank
Humidity 76% (+/-2%) (Vent at night if needed)
12 hour light cycle
Fresh water- space will be tight in a 10 gallon tank but provide the best dish you are able to fit.
Ocean water-space will be tight in a 10 gallon tank but provide the best dish you are able to fit.
Decorative plants for cover. You can add hiding places now too.

General

Maintain this level for 5-7 days. If your hermit crab digs down to molt at this stage, that is ideal. If you are introducing more than one new hermit crab and some go down and others don’t, you can do one of two things: Do nothing, leave the crabs in isolation until they dig down too. As molters surface, move into the main crabitat. Or leave only the molters in the isolation tank and move the others into the main crabitat.

Notes: If you are also dealing with mites or shell disease you will not want to introduce the new crabs into your main crabitat until you are certain they are healthy. Even if it takes longer than this method requires. You will put your healthy hermit crabs in jeopardy by exposing them to sick crabs.

Surface Molt

Your new hermit crab may surface molt while in the midst of the adjustment protocol. This is not a reason to panic. If the hermit crab is the only crab in the isolation crabitat, do nothing until the molt has finished, the exoskeleton is hardened and the hermit crab has consumed all of its shed exoskeleton. Maintain the current stage of the protocol. When the hermit crab has recovered from the molt and shows normal activity level, finish the protocol as described.

If the hermit crab is not alone it must be protected from it’s tank mates. Ideally you will not touch or move the molting hermit crab and instead cover it with a two liter bottle or plastic bowl. Add some vent holes and place a weight on top to keep the other hermit crabs OUT. Risk of cannibalism at this time is high. Additional information on hermit crab surface molt.

Original method created by Sue Latell in 2008 in collaboration with a DVM and marine biologist.

The method explained in a video by Crab Central Station

References

Thacker RW. Avoidance of recently eaten foods by land hermit crabs, Coenobita compressus. Anim Behav. 1998 Feb;55(2):485-96. doi: 10.1006/anbe.1997.0621. PMID: 9480714.
Crustacean Nutrition. (1997). United States: World Aquaculture Society.

Original Method for reference

written by Sue Latell March 8, 2006

Definition:

PPDS 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 deprivation, 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).

Principals:

PPDS 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 PPDS 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 PPDS is really a generalized procedure that will work no matter what the degree of PPDS is.

Factors:

Set-up:

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.

NOTE ABOUT PPDS MOLTERS:

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 12 hour light cycle either. If needed for some shelter, just drape some sort of plant along the outside of the bottle.

Behavioral:

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 PPDS. 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 ground cover. 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.

Materials:

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.

Method:

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:

Environment:

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.

General:

Keep the sand as dry as you can. Condensation and wicking from the moss may be a problem, but is usually offset with the 12 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:

Environment:

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.

General:

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:

Environment:

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.

General:

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.

Overview:

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.

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).

Offering greensand and worm castings is recommended at well. When hermit crabs won’t eat anything they will almost always eat both of these highly nutritious foods.

7 Day Metabolic Menu

Day 1:

(WILL INSERT MENU LATER)

Written by: Susan Latell

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

Meta

Translate

Introduction:

Why should I do this?

Notes:

Supplies:

Feeding routine:

What to feed:

How often do I feed from each group?

Stage 1

Environment:

General:

Stage 2

Environment:

General:

Stage 3

Environment:

General:

Stage 4 (optional)

Environment:

General

Surface Molt

References

Original Method for reference

Definition:

Principals:

Factors:

Set-up:

Behavioral:

Materials:

Method:

Stage 1:

Environment:

General:

Stage 2:

Environment:

General:

Stage 3:

Environment:

General:

Overview:

Dietary requirements:

7 Day Metabolic Menu

Day 1:

Share this:

Like this:

What’s New at CSJ

Public Statement on Intellectual Property Infringement

Why Wild Hermit Crabs Need Seashell Projects: Saving Their Natural Homes

The Crab Street Journal Celebrates Its 23rd Birthday October 17th 2024!