Tag Archive for shell

An Argument for Isolating Hermit Crabs

Hermit crab with black spot shell disease

Hermit crab with black spot shell disease

When adding newly purchased or acquired crabs to an existing colony, for the long-term health of all, we at CSJ recommend the use of an isolation tank. Placing newly purchased or adopted hermit crabs into an existing healthy colony without a quarantine period risks the unnecessary exposure of your healthy hermits to shell disease or parasites.

If you are just starting out with hermit crabs and do not have an existing colony or crabitat in place, use of the PPS Reduction Method will allow you to monitor your new crabs for 30 days and bring them slowly up to ideal environmental conditions.

The PPS Reduction Method should be used with all newly purchased crabs unless you have visually confirmed that they are from a setup with sufficient heat and humidity. This is a 30-day process, allowing sufficient time to identify signs of illness or parasites, and reduces the number of hermit crab deaths due to PPS, most of which occur within the first month but can occur up to eighteen months post-purchase. The first molt for a hermit crab in your care is the biggest hurdle in overcoming Post-Purchase Syndrome.

For adoptive hermits coming from an ideal environment, quarantine conditions should be set at recommended heat and humidity levels for an established crabitat. However we still recommend the use of shallow substrate to allow for easy visual inspection. If you prefer to allow them to dig down, plan to quarantine for 60 days instead.

If the hermit crabs are coming from an unknown environment, the PPS Reduction Method provides the needed quarantine time not only for combating PPS but also for shell disease or parasites.

Shell Disease Syndrome includes a number of exoskeleton-related bacterial infections that are easily transmitted to healthy animals. Most infections are external-only and do not affect underlying tissue unless there is cross-exposure and re-contamination while molting. (There is, however, one variant that causes the exoskeleton to fuse with underlying tissue, preventing a successful shed and resulting in death or deformity.) Crustacean shell disease is highly contagious and spreads rapidly in an artificial environment. Wild-harvested hermit crabs are warehoused in dirty, overcrowded conditions and then shipped to pet stores. One crab could expose many other crabs, particularly those made vulnerable from physical stress or injury. New crabs should always be inspected for damaged exoskeletons both at the time of purchase and prior to adding to an existing colony. When purchasing a hermit crab with visible damage, said crab should be kept in quarantine until successive molts have repaired all signs of damage or disease. At the time of writing this article, it is unclear if the bacteria that causes shell disease can survive in the substrate, so it may prove beneficial to give the hermit crab a gentle bath in ocean water before placing in the main crabitat. As a rule we do not recommend forced bathing but in this instance you do not want to risk carrying contaminated substrate into the main crabitat, thereby placing your entire colony at risk.

Mites or other parasites can hide in the shell of newly purchased hermit crabs. This is especially true of hermit crabs purchased from filthy conditions where dead hermits are present. Before selecting new hermit crabs, check them over carefully for mites or other bugs, both on the body and the shell—exterior and interior. Red mites attached to the leg joints or gills are parasitic and harmful. In rare cases there may be fly larvae inside the shell where you are unable to see it. If the store habitat is especially dirty there is a higher likelihood of phorid flies and other fly larvae being present. You may not be able to easily see mites or parasites so visual inspection does not mean it is safe to place them in the main crabitat with your healthy colony. Quarantine for 30 days and check daily for signs of mites.

If shell disease appears in an existing colony, the scenario is more complicated due to the possible contamination of substrate coupled with molters still underground. Infected crabs should be moved immediately to a quarantine tank with minimal substrate until they have molted and show no signs of infection. This may precipitate a surface molt, but that is preferable to re-infection from digging into contaminated substrate. For the main crabitat, consider replacing the substrate and sanitizing items in the tank once all molters are above ground. This may be exercising an abundance of caution, but I do believe that an episode of contaminated substrate (ten years ago) is what killed my colony of Coenobita compressus (as well as some of the other species), halting their molts and trapping them in their exoskeletons.

We do have a recipe for a hermit crab medicinal bath that may be beneficial in treating shell disease.

Measuring Hermit Crab Shells

Wee wants to be big so bad

Wee wants to be big so bad

**A newer version of this article is available:


Hermit crab shells sold online are typically sold based on the size of the opening. When purchasing new shells for your hermit crab, measure their existing shell and then choose several shells that are somewhat larger. Hermit crabs typically prefer a shell that fits snugly allowing them to fully seal off the opening to protect themselves from predators and dessication.
The photo shows how to take measurements properly.

Measuring hermit crab shells

Measuring hermit crab shells

Ecuadorian (C. compressus) typically prefer a shell with a D shaped opening and commonly wear shells that are too small.
Other species will wear a variety of shells, both with circular and D shaped openings.


Circular opening shell


D shaped opening shell

D shaped opening shell


My shell is too small!

My shell is too small!


Coenobita cheliped pincer claw

My shell fits just right!


Hermit crab grooming

Coenobita perlatus grooming itself - Photo by Stacy Spangler of Isopod Connection

Coenobita perlatus grooming itself – Photo by Stacy Spangler of Isopod Connection

In hermit crabs, the fourth and particularly the fifth pereopods are reduced, usually remaining within the confines of the gastropod shell and hence are not used for walking. These appendages do however becoming important when the hermit crab attempts to right itself, providing anchorage within the shell. Further, the fifth pereopod has become specialised as a gill cleaning appendage, often resting within the gill chamber (Bauer 1981). On the abdomen only the left pleopods are retained (Poore 2004).[1]

Hermit crabs used specialized setae on the third maixillipedes and fifth pereiopods for most grooming but used the unmodified first, second, and third pereiopods as well. Most brachyuran grooming was performed with modified setae on the the third maxillipedal palps and eipods, with a row of simple setae on each chelipede merus, and with the chelipede fingers.

The third maxillipedes and fifth pereiopods performed the majority of movements, including all of the more complex actions, and were suprisingly dexterous. Coenobita clypeatus devoted most of it’s grooming energy on the eyes and anntennules and did so with the mesial surfaces of the dactylus, propodus, carpus, and distal merus of the third maxillipedal endopods.

The three pairs of walking legs (chelipedes included) groomed themselves by scrubbing against each other in various combinations of two or three appendages. In addition, the fingers of the minor chelipede picked at the surface of the major chelipede. The chelate fifth pereiopods were quite flexible and extended as far forward as the chelipedes. The fifth pereiopods also groomed most of the central and posterior carapace, including the branchial chamber, and much of the abdomen. The fifth peeriopods groomed much of the shell’s interior, particularly the columella and innner and outer lips, as well as the exterior lips.These appendages did not function exclusively as grooming organs, as they also use their laterally situated gripping scales to brace the body against the shell (Johnson 1965, Vuillemin 1970).

After every few grooming acts, the fifth pereiopods moved anteriorly, in unison. to meet the two third maxillipedes, which were extended posteriorly beneath the body. The plumodenticulate and serrate setai of the posterior appendages were then scrubbed by the maxillipedes. The third maxillipedes, in turn, were scrubbed against each other and/or against the second maxillipedes after a grooming bout. The interior mouthparts had a self-cleaning function as well.

Thus, the maxillipedes groomed the anterior portion of the body (especially the sensory structures), the walking legs groomed each other, and the fifth pereiopods scrubbed the most posterior areas. Two movements were, at times, performed simulanteously, e.g., mutual leg scrubs and anntennule grooming. Although grooming may occur at any time, it was most frequentl and intense immediately after a ran and was often performed in standing water if it was available. Water is clearly an important debris-flushing medium. The grooming setae, parrticuarly the serrate setae, may also serve in a sensory capacity (Derby 1982).

Foam bathing, in which bubbles produced by the mouthparts disperse fluid about the body, occurred in partially submerged or emergent crabs. This action has been variously interpreted as a method of thermoregulation, pheromone distribution, water reserve aeration, or cleansing (Altevogt 1968, Wright 1966, Lindberg 1980, Jacoby 1981, Schone & Schone 1963, Brownscombe 1965). [2]

Dardanus megistos by Storm Martin 2012
2. Grooming structure and function in some terrestrial Crustacea

Ask Milo-Post Molt Shell Change

Stephanie asks:

I’ve had my hermit crabs for a few months and I have noticed a couple of things. One of my crabs molten but did not change shells, is that weird. Also, my crabs stopped moving around inside the tank. They never are active. What should I do?

Hi Stephanie!
It is a common misconception that hermit crabs must change shells when they molt. This is not true. Hermit crabs change shells when they decide it is time. A molt can trigger a shell change if the shell was very small fitting prior to molt. You can’t control when your little guys change shells so always have 4 or 5 empty shells per crab for them to choose from.

If your crabs are never active the first thing you should check is your temperature to make sure it is in within the ideal range of 72-82F. Also make sure your humidity is a proper levels. Hermit crabs are primarily nocturnal so they are the most active at night. It could be possible you aren’t awake to notice their movements.

Hope this helps!

Your friend in a pinch,

FAQ When do hermit crabs change shells?

Shell Changing Queue - Photo by Brian Hampson

FAQ When do hermit crabs change shells? Shell Changing Queue – Photo by Brian Hampson

**A newer version of this article is available: http://crabstreetjournal.org/blog/2018/02/11/land-hermit-crab-shell-guide/

Shell Changing Queue - Photo by Brian Hampson

Shell Changing Queue – Photo by Brian Hampson

Note: Fun shell changing videos at the bottom of the post.

crab_crazy asked:

Hi yall! About how often do hermies change there shells? I provide them with shells all the time! Two of my hermies just changed there shell! They look really cute, but, anyway. I was just wondering. Thanks yall!


Hi, Ronni,

Well, there is no exact answer to your question. Some crabs change shells all the time. My Fifi, a PP, after her first molt two months ago, has changed shells at least six times. She went hog-wild after I bought a lot of polished tapestry turbos on eBay.
Most of my crabs have either changed shells after a molt, or, in the case of new additions, immediately upon arrival because the shell they were in was damaged or painted.

Ecuadorians (c. compressus) are notorious for not wanting to switch shells. I had one switch right after I got him because his shell was too small, but of my other three, only one has switched. She has done so twice, again, only after molting. Of the other two, one has molted and has kept his original shell, and the other hasn’t molted yet. I sure wish he would, though, because the shell he’s in is possibly the ugliest shell I’ve ever seen.
Basically crabs will switch when they want to, and there is no hard and fast rule regarding when and how often. All you can do is keep a good supply of crab-friendly shells in your tank in appropriate sizes, and let them do the deed when they want to. Even if they don’t change into shells very often, they will spend a good deal of the time investigating every shell in the tank, whether it fits them or not. It’s one of their forms of entertainment, along with climbing, hiding and foraging. It’s best to keep at least three shells for every crab you have, one slightly smaller, one the same size, and one slightly bigger than the shell each crab is currently wearing, if at all possible. Also, having extras so you can rotate the stock occasionally will keep them more entertained and increase the chances of a switch.


I have a crab, Sabastion (Sab), who is too be for his shell, no matter how hard he trys to hide two or three of his walking legs are parially out, but he refuses to change shells. Any suggestions?


One of my crabbies look like he really needs to change shells but he hasn’t yet. The shell he’s in is looks like its getting too small for him and yet he refuses to change into another one. He’s been in there for a while. I’ve got tons of shells for him and the others to change into. Is this normal? I’ve got all shapes and sizes of shells (all non-painted of course) and different openings. Owning crabbies isn’t as easy as I expected.


There are times this does happen. The crabber thinks the shell isn’t a proper fit, yet the hermie just refuses to change shells regardless of the selections provided. The most one can do is offer a large variety of shells, and if the hermie finds that perfect shell many times they will move when they feel they need to. There are times too that the hermie seems to be a bit stubborn about change, especially if it is an E hermie. Sometimes it does help if one boils the shells to get the scent off of them to encourage the hermie to relook the shells over. By boiling it makes them think it is a new selection of shells. A few crabbers have had some luck by putting the hermie in need into iso with a wide selection of shells to choose from. This might make the hermie a little more secure about changing shells. No need to be concerned over their original shell being shell snatched while shopping.


Before boiling any shells I always let them sit in IO water for about 30 minutes. I’ve just heard too many stories about shells that look empty being , well, not empty. 30 minutes in the water will make even a stubborn crab emerge.
Here’s one of my stubbornest.

Hermit Crab in a Snail Shell

Hermit Crab in a Snail Shell

Hermit Crab in a Snail Shell

Hermit Crab in a Snail Shell

I know you can kind of see him beginning to peek out in the first one because he was getting curious but when he’s fully withdrawn, he’s invisible and because that shell is so light, it doesn’t seem overly heavy when you pick it up.


Fantastic point to bring up LolaGranola! *Clap* There haven’t been many, but have been occasions when hermies have been boiled due to not being able to see them within the shells. There was one that I remember reading that was sadly baked too due to the crabber not seeing the hermie within the hole of a choya log. Sad By the time she heard the clunk in the oven it was too late. Doing a complete ‘head/antenna count’ should be done before boiling or baking.


do they change shells only after a molt? do i need to buy the same shell he has. it looks to be his origanal one. its old looking.


Shell switching isn’t necessarily always tied to moulting. Some will change right away, some prefer to stay in their old shells. If the shell they are in fits and they are comfortable in it, they will stay put until they find one they like better. Some will change for no apparent reason and some will switch often (sometimes several times a day – going back and forth to/from old to new shells). If yours is having trouble fitting into it’s shell when it pulls itself in, you’ll want to supply it with a few more (at least 2-3 to choose from) in bigger sizes. Also, some species tend to be more into shell swapping.

A couple of things to look for…
*Different species have different body shapes so you’ll have to know which you have. If a Purple Pincher, stick with shells that have a more round shaped opening. If a Ruggie, go for more oval or “D” shaped openings.
*For size, it will depend upon how much too small the current shell is, but start with at least an 8th to a 4th of an inch wider than they are currently in when you measure across (side to side) the opening.
*Look for clean, smooth interiors and make sure there is no debris from the previous inhabitant stuck inside. Boil them and shake to listen for anything rattling inside and/or use a small baby bottle brush to clean around the curve inside.
*Look over the outside of the shell too – if there are any holes that will allow water to leak away from the Crab’s body inside the shell, discard the shell or use it somewhere else for decoration. A hole in the shell will allow the crab’s body to dry out or sand and grit to get in, harming your crab. A dry crab can’t breathe properly.
*Painted shells or natural is a personal choice, but most here recommend avoiding painted shells at all costs. Paint can chip off and is toxic to crabs if they eat it. There are tons of beautiful natural shells available that are better for the crab’s health.
*Where to find shells? We each have favorite places to look but Naples Seashell company has been a good choice for us. Their shells are measured for you and I haven’t gotten any yet that were damaged or unsuitable. They have a whole section on just Hermit Crab shells. Other sources if you are willing to go digging, are craft stores. Look for mixed baskets and discard the unsuitable ones – using the good ones. These baskets often come with many shells in them and the oyster or clam shells make nice little treat or feeding dishes. Other tiny shells in the basket can be glued onto containers for decoration.


Nearly all of my PPs, Strawberries, Indos and Ruggies greatly prefer turbos (round openings). The Ecuadorians really like the nerites, whale eyes and babylonia spirata (oval/D-shaped openings). I’ve posted this before, but there’s an eBay store, The Hermit Crab Shack, that has all natural shells at good prices, and Mike that runs it is very good about honoring requests about specific sizes, etc. Some of my crabbies have been in the same shell for nearly two years, and others switch on a regular basis. Happy shopping!


All our species of hermies Straw’s Rugs, Indo’s, and PP’s are in turbo shells too. Majority of our E’s are in turbo’s as well with only a couple who are in the shells with the D opening.

Sara Lewis and Randi Rotjan, New England Aquarium and Tufts University: Hermit Crab Vacancy Chains:

From BBC One: Hermit Crab Housing:

Photos of Coenobita Cavipes lining up for a shell change in Singapore

HELP! My Hermit Crab has left its shell! What do I do?

A hermit crabs shell serves two purposes: first protection of the soft abdomen and second it prevents dessication (drying out). A hermit crab that has left the protection and life-sustaining seashell home is telling you it’s in distress.

Coenobita brevimanus shellless

Coenobita brevimanus shellless


  • Physically stressed from poor handling or conditions during capture, transport and/or poor pet store conditions
  • Shell fight-another hermit crab has taken its shell-no suitable shell remains
  • Changing shells and let go of the old one, which was shell-napped by another crab-no suitable shell remains
  • Foreign body/irritant in the shell (sand, pest, fungus NOTE: crabs have been known to hide food in their shell)
  • Temperature is too HIGH
  • Humidity is off
  • Pre-molting, although it rarely happens


Below we expand a bit on these causes.

Physical Stress

Land Hermit Crabs endure a great amount of stress before reaching the pet store. The harvesting and shipping of hermit crabs is a very inhumane process and the crabs suffer because of it. They then arrive in pet stores, who in most cases, don’t know how to properly care for them. They arrived stressed out, dehydrated and hungry. Then you purchase them and take them home. Now severely physically damaged the hermit crab will often leave its shell to die.

Shell Fight

If there is not a variety of appropriate styles and sizes of extra changing shells in the crabitat for the hermit crab to choose from, there may also be shell fights. This is normally dangerous for the hermit crabs within the crabitat due to the fact that hermit crabs would rather let themselves be pulled apart as opposed to giving up their protective home. Many times this leads to a hermit crab being seriously injured or even killed by the aggressive hermit crab in search of a comfortable shell.
There are times too when a hermit crab is shell shopping and may of let go of his original shell to try another on and has his shell taken by another tank mate. This forces the hermit crab to find another shell, if a suitable one isn’t available it is left homeless.

Foreign body

Something may have got into his shell and is irritating his soft abdomen. One can rinse the shell out with dechlorinated water, but many times if something is lodged within the shell this doesn’t help much. Boiling the shell in dechlorinated water and giving it a good shake will many times dislodge anything that may be within it. There maybe pests or a fungus within the shell that is irritating his abdomen and will cause him to leave the shell.

Incorrect environment – too hot, too much or too little humidity

If the hermit crab is too warm, to try to cool off a hermit crab will leave their shells. To prevent over heating it is very important to monitor the substrate temperature as well as the air temperature. The temperature at the warm end of the crabitat should be approximately 80-82F.  At 85F or higher this is nearing too warm for most hermit crabs to be comfortable (some species do enjoy higher temperatures). The temperature at the cool end of the crabitat should be approximately 72-75F. Hermit crabs are ectothermic creatures and must have the variance of temperatures to self regulate.

If the humidity level is too low in the crabitat hermit crabs feel as though they are suffocating. In hopes of relieving the discomfort they are experiencing they leave their shells. If they had been subjected to a too low humidity, too many times it has already caused irreversible gill damage. For a more accurate humidity percentage reading level, the humidity gauge should be located close to substrate in the middle of the tank away from water sources that can affect the gauges reading. The safe range is 70-80% relative humidity. Cheap analog gauges from pet stores are rarely accurate.

Please calibrate your humidity gauge to ensure how accurately it is reading:

A hermit crab will also leave their shell due to a too high of a humidity percentage. A high humidity level makes it difficult for the hermit crab to breath due to the ‘thicknesses’ of the humidity. If subjected to a too high humidity level, this can promote a gill infection that may cause irreversible damage. Maintaining humidity levels of 90% and higher is discouraged.

And even though it is rare, he maybe in premolt or be molting. Pre molt symptoms

How to gently coax a hermit crab back into their shell

Wash your hands.

For a hermit crab who has gone naked to surface molt or come up from molt naked and still soft please jump down to the NOTE section.

Rinse or boil the shell in dechlorinated water and shake it to remove anything that maybe lodged within it. Pour out most of the water from the shell. Place the shell in the bottom of a cup or small bowl depending on the size of the crab. The container should be JUST big enough for the crab and the abandoned shell. Add a small amount of dechlorinated water the bottom of the cup. This will help keep the crab moist and may help the crab re-shell.

Wash your hands.

If the hermit crab is not in mid molt or still soft from molt, gently pick the hermit crab up by lightly holding it just behind the last pair of walking legs. You can also use a large spoon to scoop him up very gently. Carefully examine the abdomen for any signs of irritation being very careful he does not attempt to escape and injure/kill himself. Examine for any molting symptoms as in transparent eyes, lifting of the old exoskeleton, water sac, etc. Lethargy can be a sign of pre-molt or death.

Lower him into the cup next to his shell. Cover the cup with a washcloth to make it dark. Transfer the cup to an isolation unit where the temperature and humidity are within proper ranges OR back into the main tank. Ensure other crabs in the tank are not able to climb into the cup.

Leave the hermit crab in darkness and quiet for a while and it may return to the shell.

After a few hours if the crab still has not re-shell you can attempt to manually place him back in his shell. If the crab is visibly weak it likely will not be able to hold the shell, if this is obvious do not attempt to manually re-shell.

Being very careful and gentle moisten/mist or dip the hermit crabs abdomen with dechlorinated water and try to slide the tip of hermit crabs soft abdomen within his moistened shell making sure it does not scrape or injure the hermit crab. It may be easier to prepare a dish of dechlorinated water, then place both the shell and crab in the water. The buoyancy will make it easier to coax the abdomen into the shell.

If the crab will not or can not hold on to the shell do not continue to force. Try a couple of times and then stop. If the crab is still naked you can move to a slightly larger containment area like a small kritter keeper. Add a few more shells that might fit the naked crab to the kritter keeper. Transfer the naked crab and the original shell to the kritter keeper. Offer some honey, worm castings, scrambled eggs or other favorite food to encourage eating. Place the kritter keeper inside of your isolation tank or in the main tank. It is important the hermit crab remain in the correct heat and humidity.

If the crab still will not take a shell there is little else to do but keep him comfortable and wait. Continue to offer food and water, maintain humidity and heat.

Note: Molting or recently molted crabs should be handled differently. If the crab is still soft or molting, use our 2 liter bottle method (cut off the bottom and place over the crab like a dome) to isolate the crab within the tank. Be aware this does not protect from crabs digging in from below so please keep an eye on the crab. If your other crabs seem overly interested you may need to transfer the crab to a secure container within the crabitat. Use a clean glad ware type bowl with a lid. You can poke holes in the lid. Use a clean spoon or similar scoop to gently scoop up the crab by digging slightly into the substrate below him so that the body is still resting on the substrate and not touching the scoop. Gently place in the bowl along with the most recent shell and one or two other options.  Do not add water to this bowl because of the soft exoskeleton. The crab is going to be exhausted and likely will be unable to take a shell until it has fully hardened and regained energy.  If the shed exo is available be sure to put it in the bowl along with some water and other foods.  Our Hermit Crab Feeding Guide can direct you to the most beneficial foods at this time.

If you need any further help, please read the Emergency Help Article.

Medicinal Bath for treating bacterial infections, shell rot and black spots.

This recipe can be modified, made stronger for use with very sick crabs, although this strength is fine for more minor cases!

Medicinal Bath created by Gertrude Snickelgrove and updated by Sue Latell of CoenobitaResearch and CSJ

Ingredients for Medicinal Bath for Hermit Crabs created by Gertrude Snickelgrove and updated by Sue Latell of CoenobitaResearch and CSJ

General wash for injured crabs:
1 Tbsp. Marshmallow root shaved
1 Tbsp. myrrh powder
1 Tbsp. calendula (marigold)
1 Tbsp. whole chamomile flowers (not powdered)

First, you’ll need to make a decoction. Take one quart of water, and heat it over the stove to near boiling. Add one tablespoon marshmallow root, and one tablespoon myrrh. Cover, and simmer for thirty minutes. Remove from heat. Add one tablespoon calendula flowers (marigold) and one tablespoon whole chamomile flowers. Cover immediately again. Let sit until cool, then strain herbs out and refrigerate. It will last a max of 48 hours. The herbs are all safe, they can even be fed to the crabs. I routinely feed calendula and chamomile to mine.

When bathing the crabs, bathe the affected parts only. I don’t see any need to get the stuff on the gills, unless there is an infection of the abdomen. The reason I say this, the marshmallow root makes a slime coat, which is sort of thick, and is not beneficial in the shell unless you’re fighting an infection in that area. If the infection is in on gills or soft tissue you can leave out the marshmallow root.

These are some of the general benefits of these herbs:

So marshmallow root draws out infections, draws out splinters, and makes a thick slime coat layer that helps prevent infection and aids in healing.

Myrrh powder (like what was given to Baby Jesus), is a powerful anti-bacterial, yet unlike antibiotics, is completely safe for crustaceans.

Calendula flowers (marigold), gently stimulates the immune system, is a mild anti-bacterial and anti-fungal, and cuts down on healing time.

Chamomile flowers, reduces inflammation, helps to speed healing, and reduces swelling when it is present.

A few words of caution: do not use powdered herbs; you really need to find the bulk medicinal herbs, because too many properties evaporate when the herbs are crushed. If you drink chamomile tea, and do not find it that relaxing, you should try a cup made from the whole flowers. There is a noticeable difference.

And second, all the properties of chamomile (the essential oils) evaporate with the steam. That’s why, when cooking herbs that have any essential oils, you must trap all the steam and let it cool, so the medicinal contents will remain in the formula.

Specific Wash for Bacterial Infection (including shell rot if caught in early stage):

2 cups dechlorinated water
1 Tbsp. myrrh powder
2-3 Tbsp. calendula (marigold)
1 Tbsp. whole chamomile flowers (not powdered)

Veterinarian recommendation: place the crab in clean sand, increase light exposure and bring humidity down to 70% and maintain there. Lower humidity retards the metabolic rate of the bacteria but 70% is the lowest a crab can tolerate while being treated. This must be done in isolation. Bacterial shell diseases are highly contagious but can be shed with a good molt.

This concoction should be steeped after the water is boiled. Let it sit for about 20 minutes, strain out petals. Wash should be applied 2 times a day for 3 days, let the crab sit in it as there may be lesions on his shield and abdomen. It will benefit him if he retains it as shell water. After the first few days if you notice more lesions forming or see more discolored depressions in his chitin, you may not be able to stop the progression of the disease.

If you do notice that there is no more formations, change out the substrate for new and watch him in ISO for at least another week. You can repeat the process again if you see reformation occurring. I think it would be up to you if you want to continue, but remember to keep this crab separate until you are sure that he has no active growth of the bacteria on him. With my indo BOB, he remained in a 2.5 gal ISO until he molted.

Here are his pictures:

Bob came up from his molt like this. This spot was suspected shell rot. The deformation of the claw is from an unidentified toxic substance, or even from the bacteria being present when he molted the first time.




This was after his molt and after the bath treatment. I think it contributed to him molting again so soon, and while his claw still is undercut, there was no spot or depression in his chitin.




Sorry for the poor quality of the pictures, I lost the originals when I had a hard drive crash.

Photos from Daethian:


Hermit crab with black spot shell disease

Hermit crab with black spot shell disease


Hermit crab with black spot shell disease

Hermit crab with black spot shell disease


Hermit crab with black spot shell disease

Hermit crab with black spot shell disease


Hermit crab with black spot shell disease

Hermit crab with black spot shell disease


The main recipe was given to Daethian(Stacy Griffith) via email from Gert Snicklegrove in 2005. The best of our knowledge she is the creator of this recipe along with Summer Michaelson.

The second portion is an adaptation created by Sue Latell of Coenobita Research after speaking with her vet in 2006.