Technique for Adjusting PPS Crabs – Method

 written by Sue Latell March 8, 2006

Definition:

Hermit crabs enjoying some moss while their tank is being cleaned!

Technique for Adjusting PPS in Newly Purchased Hermit Crabs

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).

Principals:

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.

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 PPS 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 12hour 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 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.

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 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:

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.

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. 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.

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.

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

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