Tag Archive for good

Land Hermit Crab Shell Guide

Wee wants to be big so bad

Wee wants to be big so bad

A hermit crab’s shell is his home and his protection from predators and desiccation. Hermit crabs take up residence in discarded shells and can not make their own shell. When kept as pets it is important that you choose suitable shells for your hermit crab. Provide 3-5 suitable shells per hermit crab. Shells can be placed directly on the substrate or in a designated bin that we call a Shell Shop. This helps keep the shells clean and reduces the chances of them being buried.

In semi-terrestrial hermit crabs a well-fitting shell is essential for maintaining low evaporation rates and carrying ample water. An appropriately sized shell in good condition allows invasion of inland environments offering more shade, food and fresh water for C. clypeatus studied on Curacao. Hermit crabs with broken, ill-fitting shells are restricted to the coast, must rely on drinking saltwater, and appear to be in relatively poor condition.[1]

Terrestrial hermit crabs show “shell facilitation”; that is, larger populations of crab generate, through wear, larger numbers of shells suitable for adult crabs. [2]

Hermit crab’s should be allowed to choose the shell they prefer from a selection of different sizes and types of shells. Natural shells are the best option. Painted shells should be avoided. Shells should not have jagged edges or holes in them.

Most species of hermit crabs will prefer a shell with a round opening. Coenobita compressus (Ecquadorian) prefers a shell with a D shaped opening. Coenobita violascens prefers a long spiral type shell.

Shells should be cleaned and boiled in Prime treated water before offering to your hermit crabs. Many owners also do a final rinse in ocean water before placing in the crabitat but this is not required.

***If you collected shells from the beach be sure the shells are EMPTY before bringing them home.

Hermit crabs can be very stubborn about changing shells but do not attempt to force a crab from it’s shell.

How to measure the opening of the shell.


My shell is too small!

My shell is too small!

Coenobita cheliped pincer claw

My shell fits just right!


Shape – Round Opening


Shape – D Opening


Good shells preferred by C. violascens

C. violascens enjoy long spire type shells.


Unsuitable Shells


Good but usually ignored

When and why do hermit crabs change shells?

Contrary to common belief, a molt does not mandate a shell change! If the existing shell is roomy enough to allow for growth during a molt, the hermit crab may feel no need to change shells. Additionally, you will find some hermit crabs are chronic shell shoppers, always trying on something new.

The Social Lives of Hermit Crabs

 

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

References:
1. Wilde, 1973
2. Abrams 1978

Pet Store Letter Writing Campaign

Pet Store Letter Writing Campaign

Pet Store Letter Writing Campaign!
Wait a minute Mr. Postman – Photo by Mary Milhorn

Our pet store letter writing campaign is a simple way you can advocate for the proper care of land hermit crabs in pet stores.

Pet Store Appeal Packet

In our Pet Store Appeal packet we have a pre written letter that anyone is free to use. It is a form letter that allows you to add your name, signature and contact info to make it more personalized. This is perfect for anyone who wants to work one on one with their local store to make improvements but needs some help opening the door. This letter comes with a special two sided caresheet that can be left at the store if they are open to it. Feel free to make as many copies as you want.

 

Letter Mailers

For those of you who want to help but don’t feel comfortable working one on one with a store, we can help! We are creating a team of letter mailers who will reach out to pet stores that we are notified about. Mailers will reach out either via email or snail mail.

Pet Store Report

If you are personally aware of a bad pet store we encourage you to fill out the Pet Store Report Form so that we can follow up with that store.

If you know of a store that is doing a great job, please fill out the Pet Store Report Form so that we can reach out and thank them. We will also invite them to apply for LHCOS Approved Store status. A great honor no doubt!! Not only that, but it may draw new customers to a Pet Store that has quality products, service and has shown that they care about the health and well being of  land hermit crabs 😀

Other ways you can help:

Send a letter yourself!

We have made our letters generic with our contact information on them. That means you can mail out the letter and caresheet and if the store is open to working with us, they will have our email address to reach out. You can remain anonymous.

If sending via snail mail feel free to use our return address:

The Crabstreet Journal

403 West Washington Street

Wayne City IL 62895

Spread the word!

Across all platforms (website and social media) all members can and should encourage other hermit crab owners to fill out our Pet Store Report Form. If you encounter someone posting about a bad pet store, definitely encourage them to fill out our form. Explain they only have to fill out the form and our team will take it from there and make contact with the store in an attempt to improve the situation.

Submit to the team!

Actively monitor Instagram, Facebook, Twitter, Google+ for pet stores that are advertising that they sell hermit crabs. Send the store name and location to the team via crabstreetjournal+petstorereport@gmail.com

A screenshot of the post itself would be so very helpful too! The team will take it from there.

Volunteer!

We are actively looking for other mailers! If you are outside the U.S. and want to be a mailer for your location that would amazing!


Pet Store Report Form:

https://docs.google.com/forms/d/1rhJvUpA1OHo5U0POCasHTABDKqc6waPh9P_LMd5085I/viewform


Customizable Letter:

http://crabstreetjournal.org/download/Hermit-Crab-Letter-revised.docx


Generic Letter

http://crabstreetjournal.org/download/Hermit-Crab-Letter-Generic-Not-Fillable.docx

Mites: Friend or Foe? The Happy Tale of the Hypoaspis Mites

written by Kerie Campbell 2005

Two months ago, during deep clean, I took my largest compressus,Houdini, out of the tank, turned him over to have a look, and a red…thing fell out of his shell. I couldn’t believe it! Mites!Huge, red mites. Houdini had a few, Fifi had some, and poor Ghidra,a pre-molt rugosus, was covered with them.

I was appalled. I inspect new crabs when I get them for mites, and have never seen any. The only explanation I have is that these mites, being a bright red color, must have snuck in on some of the perlatus – they are the same color red. I have seen these mites on my gray crabs, the brown ones and the beige ones, and still haven’t seen them on the perlatus. My eyes are just not good enough to find them on the red crabs.

Another thing that made me think these mites came from the perlatus was that they were completely unfazed by a prolonged salt water bath. Mites are supposed to float off the crabs, and if they were another type of mite, perhaps they would have. But they held on to the setae for five minutes under the water and never a one floated up. It seems to me that if they were perlatus mites, they would be used to being dragged into the ocean for long periods of time, as the perlatus love to go swimming.

It didn’t really matter where the mites came from, however; just the fact that they were present was a problem enough. My tank is 120gallons, some of the wood doesn’t fit in the oven (or can be baked safely). The mites wouldn’t come off with a regular salt bath. I’ve read post after post of people who seem to have perennial mite problems; no matter how hard and well they deep-clean, the mites come back again and again.

Then I found two of the smallest crabs, dead in the substrate. I don’t know for sure, but I suspect the mites may have either drained them dry or stressed them so badly during premolt that they couldn’t survive. Either way, I had a real problem on my hands.

I looked around on the Web for days, trying to find a solution. I found some things that looked interesting and perhaps useful, like Zoo-Med’s Mite-Off, but couldn’t get a good answer about whether or not the products would harm the crabs. I know all about insecticides, organic and chemical, but I don’t know anything about electrically-charged colloids. I don’t know what they would do to the crabs, but I couldn’t take a chance. Not this time, anyway. I figured I’d save the Mite-Off as a drastic last resort.

Then I came across something really interesting, that had occurred to me before, but I didn’t want to try first: predatory mites. I read on several sites that people use a common soil-dwelling mite predator to combat snake mites and other mites on reptiles and arachnids. The species of mite is even one I had used in my auntie’s greenhouse to kill root aphids and thrips: Hypoaspis miles (which shall be called Hypos for short from now on).

Hypoaspis mites

Hypoaspis Miles mites
Courtesy of: http://www.pbase.com/image/104370200



Finding evidence that other exotic animal owners had used Hypos successfully, I logged on to my beneficial insect supplier and ordered one bottle of 12,500.
From: http://www.entomology.wisc.edu/mbcn/kyf302.html, a description of H. miles and their commercial use:

Know Your Friends

Hypoaspis miles, A Predatory Mite

Hypoaspis miles is a soil-dwelling, predatory mite that is native to the United States. Hypoaspis feeds on fungus gnats, springtails,thrips pupae, and other small insects in the soil. The mite is 0.5mm (1/50 inch) long and light-brown in color. It inhabits the top1/2 inch layer of soil. Females lay eggs in the soil which hatch into nymphs in 1 to 2 days. Nymphs develop into adults in 5 to 6days. The life cycle takes approximately 7 to 11 days.Both nymphs and adults feed on soil-inhabiting arthropods, consuming up to 5 prey per day. They survive by feeding on algae and/or plant debris when insects aren’t available. Both males and females are present, but males are smaller and rarely seen.Hypoaspis is well adapted to moist conditions in greenhouses in a variety of growing media, but does not tolerate standing water.Hypoaspis is currently used in greenhouses for control of fungus gnats. It feeds on the young fungus gnat eggs and small larvae and is most effective when applied before fungus gnat populations become established or when populations are low. It has been successfully used in bedding plant production, potted plants, and poinsettia stock plants. The mite is formulated in a pasteurized peat mixture for commercial use. They are usually sold in 1 liter containers,which contain approximately 10,000 mites of all life stages.Containers include a shaker lid which allows for distribution over the soil surface, after which Hypoaspis will burrow into the soil.One application can establish a mite population for an entire growing season under optimal conditions. A recommended application rate from IPM Laboratories, Inc. is 1 liter container per 1000 ft2.In vegetable production, recommended applications rates for cucumbers are 4 to 8 liters per 50,000 ft2 and 10 to 12 liters per50,000 ft2 for tomatoes, with applications being made when young plants are set out in the greenhouse.

Hypoaspsis will also attack thrips pupae in the soil, but cannot be relied on for thrips control alone in a commercial greenhouse. It may, however, enchance biological control when used in conjunction with predators feeding on thrips on the foliage. In small-scale experiments this mite reduced emergence of adult thrips to about 30%of that in controls.As with all purchased natural enemies, it is important to ascertain the quality and/or presence of mites in the container. You can do this by placing a small sample on a sheet of white paper, and examining it with a 10-15X hand lens to look for the quick-moving mites. Hypoaspis moves well on soil surfaces, so it is unnecessary to apply to all surfaces. Although they will move between plants inpots, at least every second plant should be treated. Application needs to be made early enough to allow the mite to spread. They won’t move throughout an entire greenhouse from a single introduction point. Hypoaspis doesn’t survive below the top 1/2 inchof soil, so mixing mites into the growing media prior to potting isnot recommended. In addition, Hypoaspis doesn’t store very well;therefore it should be released immediately upon arrival. The mite is compatible with insect-parasitic nematodes, such as Steinernemacarpocapsae and S. feltiae, and Gnatrol, the biorational insecticide containing Bacillus thuringiensis var. israelensis.
– Raymond A. Cloyd, Purdue University

When I used Hypos in my auntie’s greenhouse, I was astonished to see them still there two years later. This is because my auntie used hydroponics, and the medium was washed and sterilized after each growing season. And yet these hardy little insects were still managing to recolonize the individual gallon pots she kept her vegetables in. It was amazing, and I was very impressed by how persistent these little helper bugs were.

Since I had experience with them, and how and on what they feed, I was not worried they’d attack my crabs. They don’t even eat adult insects their own size, just the larvae. There is absolutely no way these specialized little fellows were going to be able to hurt the crabs. Furthermore, they only live in the top half inch ofsubstrate, so they won’t bother buried molters – as I found out just today when Mothra came up from his burrow in the main tank. He still had a couple of mites on him, but I digress…

I received my mites about a week and a half later. The shipping was more expensive than the mites themselves, as the insects need to be shipped overnight. But, 12,500 mites is less than $30. With shipping, I was out $68. I think that’s a bargain for the results I got.

At first, I was very conservative with the treatment plan. The mite container can keep the mites alive for about two weeks, so you can spread out your treatment. I put a clamshell of carrier, which was wood chips (small chips, not shavings) in one ISO, two in Ghidra’sISO, and three large ones in the main tank in strategic locations.Wouldn’t you know, one of the rugosus decided to snack on the mite carrier. No big deal, it wouldn’t be insecticidal, as it’s a carrier for insects. At least Camo got some cellulose that way, and a good dose of Hypos. Later that same day, Itchy galloped through one of the bigger dishes, and I saw her scoot off to spread the love. I rubbed my hands together with glee.

By the end of the two week period, I decided it’s better, when treating a mite infestation, to do two large treatment doses over the two week period, and put as many Hypos into a tank as feasible in one shot. It seemed to work better with more Hypos added to the tank at one time.

I used Ghidra as my main subject, as I knew exactly where she was in a small tank, and she was the worst affected by the mites. She literally had dozens of them on her, poor thing, and was just miserable. Daily, I would check her while the treatment was going on. During that time, I got impatient with the Hypos’ slowness (this being the main drawback of using natural pest control in this manner) and started using a hand mister of salt water to lightly spray the mites off the crab. Held over a bowl of salt water, they would fall off, and be unable to escape, and I could drown them allin the sink when it was over. A great many adult mites died in this fashion; this is a good thing, as the Hypos won’t eat the adults,except in extremes. Daily, fewer adult mites showed up on Ghidra. Ihave checked her a total of three times in the past two weeks, as she is in premolt and I don’t want to bother her unduly, and she hasbeen mite-free all that time. After six full weeks of using Hypos in her tank, I think I can confidently say that Hypoaspis miles are without a doubt, the most efficient, cost-effective, non-labor-intensive mite treatment of them all.

So, my recommended treatment plan for mites is as follows:
1) Order Hypoaspis mites from: http://www.shopgreenmethods.com/
Put “Hypoaspis mites” in the quick search box, and the Hypos will come up, Item Number CHM125C.

Note: This website is gone. Check this list ofdistributors of beneficial insects.

Wait patiently for your order, but prepare in the meantime.

2) Daily until the order arrives, hand mist each crab over a bowl of salt water to remove any visible adult mites.

3) When the mites arrive, set up a humid place to keep the container – even in the crabitat, with the lid on, would work. I put mine on top of a bookshelf, inside a plastic garbage bag with a wet sea sponge, with the mouth of the bag hanging down over the shelf, so that air could circulate, but the humidity would stay inside.

4) Lightly dampen your substrate, should it be dry. The mites do better in damp conditions.

5) Place shells or bowls full of carrier around the tank or tanks,about half the total bottle. I would recommend sprinkling it around,but that could set up a mold problem, and would make cleaning the substrate harder in the end. If you use incandescent or heat lighting, do this during the cooler night cycle, so the mites have time to disperse.Leave the shell or dish of carrier in until then ext treatment, in about a week.

6) Continue to mist the crabs during the treatment that have visible mites, to remove them. This is much better than stressing out a crab with an unwanted, long, ineffective bath.

7) In one week, remove the old carrier dishes and replace with new ones, using up the remaining mites in the jar.

8) See number 6.

9) In one week, remove the remaining carrier.

10) Wait patiently. In about a month or so, all crabs above the substrate should be mite-free. Mites are not long-lived species, so the ones that have escaped being removed manually will die of natural causes. The Hypos are there for the eggs and larvae.

My substrate is sand, which worked well, but for people with organic substrate like coconut fiber, I think this will work better, faster,and for longer, by the very nature of the Hypos themselves.

All in all, I am very pleased with this treatment, and I recommend it very highly. Though you can shop around for Hypos from other vendors, the Green Spot is one of the least expensive, and they always send live insects. Some of the other dealers don’t always ship live ones.

Got mites? Get some more, but get the right mites for the job: Hypoaspis miles.

Main Address
The Green Spot, Ltd.93 Priest Rd.
Nottingham, NH 03290-6204 USA

Contact Means
Dept. of Bio-Ingenuity
Tel: 603 942-8925
Fax: 603 942-8932
Email: Info@GreenMethods.com
Domains: GreenMethods.com & GreenMethodsForum.com

Kerie


FAQ What foods are good and bad for hermit crabs?

Hermit Crabs are beach scavengers and they can and will eat a wide range of things. General rules:

Photo by bird1234 (youtube)

FAQ What foods are good and bad for hermit crabs? – Coenobita perlatus eating garbage – Photo by bird1234 (youtube)


Avoid chemicals, pesticides, table salt, moldy foods, plants that are toxic to animals.

For hermit crab nutritional needs and the foods that provide them, download the nutritional food chart as a PDF by clicking in the gray box below.

Hermit Crab Nutrition Table
Hermit Crab Nutrition Table
Hermit-Crab-Nutrition-Table.pdf
270.6 KiB
3829 Downloads
Details

Written by Kerie Campbell

Fruits – Fresh or Wrinkly? I’ve read alot about fresh fruits being in their diets, which I use alot of BTW. But I’ve read alot about people putting in fruits that are old and wrinkling up. Is one better than the other?

Answer by: Kerie
Posted: Fri Mar 04, 2005 7:52 am
The crabs like it fresh, and they like it wrinkled. Mine also like stuff that’s gone mushy from being thawed after freezing. Alternating fresh and older fruit is a good way to vary their diet. The sugars and other compounds like terpenoids in the fruit will tend to change composition and break down for different flavors as the fruit ages. If it’s citrus fruit, though, you should always let it sit until it is wrinkly. The peels contain substances like limonene that act as insect repellents. Limonene breaks down quickly in the fruit peel as it ages, so letting it go wrinkly makes it much more attractive to the crabs. Citrus has compounds in the pith and stringy stuff that are extremely beneficial to crabs, such as beta carotene, and so citrus should be offered them on occasion, in order to promote a healthy diet.

What foods are good for hermit crabs?

Alfalfa
Almonds, crushed
Amaranth (Ancient grain – calcium)
Anchovy oil
Apple and natural, unsweetened apple sauce
Apricot
Avocado
Banana
Barley (calcium)
Bell peppers (red, yellow, orange, green or purple)
Bee pollen
Bilberries/Huckleberries
Blackberry leaves
Blackberry
Bladderwrack
Blueberries
Bone Meal (no additives, preservatives, sold as a supplement for people)
Broccoli and leaves
Brown rice, soy, wheat or 7 grain cereal
Brown rice
Canteloupe
Carnation flowers
Carrots (carotenoids)
Carrot tops (vit. E)
Cat Tails
Cauliflower and leaves
Celery leaves
Chamomile flowers
Chard
Cherimoya
Cherry
Chicken bones
Chicken, cooked and unseasoned (smash the bone for marrow access)
Cholla wood
Cilantro
Clams
Clover blossoms and leaves
Coconut and coconut oil
Cod liver oil
Collards (calcium)
Cooked eggs
Cork bark
Corn (on the cob, too)
Cornflower
Cornmeal
Cranberries (dehydrated)
Cucumber
Currants
Cuttlefish bone, powdered
Dandelion flowers, leaves and roots
Dates
Dragonfruit
Egg, scrambled or soft boiled
Eggshells
Extra-virgin olive oil
Figs
Fish flakes w/out chemical preservatives
Fish Oil
Flax seeds (crushed)
Flax seed oil (small amounts infrequently)
Frozen fish food (esp. algae, krill and brine shrimp)
Garbanzos (calcium)
Grape Leaf
Grapes
Grapevine (vines and root)
Green and red leaf lettuce (not iceburg; dark green)
Green Beans
Greensand
Hempseed Meal
Hibiscus flowers
Hikari products: brine shrimp, krill, crab cuisine, sea plankton (no preservatives, ethoxyquin, copper sulfate)
Hollyhock flowers
Honey (organic, or at least locally produced, for anti-microbials)
Honeydew Melon
Huckleberries/Bilberries
Irish Moss
Impatiens flowers
Jasmine flowers
Kale
Kelp (calcium)
Kiwi
Lobster with crushed exoskeleton
Mango
Marigold flowers (calendula)
Marion Berries
Mint (but not peppermint!)
Most organic baby foods
Mulberry (fruit, leaves, wood)
Mushrooms
Mussels
Nasturtium flowers
Nettle (wilted)
Oak Leaves and bark
Olive and olive oil (extra virgin)
Oranges
Oysters (zinc)
Pansy flowers and leaves
Papaya
Parsley (calcium & vit. C)
Passionfruit
Peaches
Peanut butter (avoid sugar, corn syrup and hydrogenated oils)
Pears
Pecans
Pecan bark
Petunias
Pineapple
Plain calcium carbonate powder
Popcorn (unseasoned, unflavored, unbuttered)
Potato (no green parts, including eyes)
Quinoa (New World grain – calcium)
Raisins (no sulphur dioxide)
Raspberry
Red raspberry leaves (highest bio available calcium source + vit. C and trace minerals)
Rolled Oats
Rooibus
Rose petals
Rose hips (high in Vit. C)
Royal Jelly
Salmon
Sand dollars
Sardines (calcium)
Scallops
Sea biscuits
Sea fan (red or black)
Sea grasses
Sea salt
Sea Sponges
Sesame seeds (crushed)
Shrimp and exoskeletons
Spinach
Spirulina (complete protein and chlorophyll source; highest in beta carotene)
Sprouts (flax, wheat, bean, alfalfa, etc.)
Squash and blossoms
Strawberry and tops
Sunflower Seeds (crushed), flowers and leaves
Swamp cypress wood (false cypress, taxodium sp.)
Sweet potato
Tangerine
Tomato
Tuna (zinc)
Turnip greens (calcium)
Violet flowers
Walnuts
Wasa All-Natural? Crispbread (Oat flavor)
Watercress (vit. A)
Watermelon
Wheat grass (magnesium)
Wheat (calcium)
Wheat germ (B vitamins)
Whitefish
Whole Wheat Couscous
Worm Castings
Zucchini

Other herb flowers-The tiny flowering blooms of the following spices are edible: anise, basil, bee balm, chives, coriander (cilantro), dill, fennel, garlic, oregano, rosemary, and thyme.

Bugs

Beetle Grubs
Bloodworms
Centipedes
Cicada exo skeletons
Earthworms
Feeder cockroaches
Grasshoppers
Harvestmen
Hornworms
Isopods
Katydids
Locusts
Mealworms
Scorpions
Spiders
Super worms
Waxworms

* This food list is mainly adapted from Summer Michealson and Stacey Arenella’s book, The All-Natural? Hermit Crab Sourcebook, and expanded on by Julia Crab and others

What foods are bad for hermit crabs?

While it is true that crabs are scavengers with a wide repertoire of foods they can eat, there are many plants and foods that just should not be fed to a crab. The foods on this list are to be avoided. Some are toxic, some are insect repellents or used as insecticides, and some the crabs just won’t go near, such as lemon — lemon won’t hurt them, but they certainly won’t eat it.

Aconite (Monk’s Hood)
African violet leaves
Alder bark
Aloe vera (interferes with potassium absorption)
Amaryllis
American Hellebore
Anemone/Windflower
Aniseed
Avocado leaves
Azalea/Rhododendron
Bindweed
Bird of Paradise Flowers
Bluebonnet
Bottlebrush flowers
Bougainvillea
Boxwood
Buckthorn
Buttercup
Carnation leaves
Castor Bean
Catnip
Cherimoya Seeds
Chrysanthemum
Cinnamon
Citrus (leaves and branches to be avoided; part of the evergreen family. The fruit is fine)
Columbine
Compost (unless 100% organic)
Crocus
Crown of Thorns
Cube Plant
Custard Apple (young fruit)
Cyclamen
Delphinium
Derris
Dieffenbachia
Dill
Dittany
Eucalyptus
European pennyroyal
Evergreen (pine, cedar, juniper, etc.)
Feverfew
Fleabane
Garlic
Geranium
Golden Pothos
Green hellebore
Hemlock
Holly Berries
Ivy (of any kind)
Juniper Berries
Kalanchoe
Larkspur seed
Laurel
Lavender
Lemon Balm (Sweet Melissa)
Lemon Grass
Lucky Bamboo (Dracaena sanderiana)
Mayweed
Mistletoe
Morning Glory
Oleander
Onion
Oxeye daisy
Papaya seed
Parsley Seed (fruit)
Peace Lily
Pencil Tree Cactus
Peppermint
Philodendron
Pine or cedar wood or needles
Prickly juniper
Pride of China fruit
Prunus species trees (apricot, bitter almond, cherry, cherry laurel,
nectarine, peach, plum) Fleshy fruits are edible, everything else
contains a cyanide-like compound and is fatally toxic, including
seeds, wood, leaves, bark and flowers.
Red Emerald
Rosemary
Sago Palm
Sanseveria
Schefflera
Stargazer Lily (Lilium x Stargazer)
Sweet Flag
Tansy
Tea Tree
Texas Mountain Laurel (Sophora secundiflora)
Thornapple
Thyme
Tobacco
Verbena
Vinca
Wild Angelica fruit
Wormwood
Yew
Yarrow

From: The San Diego Turtle and Tortoise Society
http://www.sdturtle.org/
And other sources

We highly recommend keeping worm castings and greensand on hand and in your tank daily. Both are highly nutritious and are loved by hermit crabs.

Awesome video of a huge  gathering of Coenobita perlatus eating garbage

FAQ How do I choose suitable shells for my hermit crab?

***Note: There is a newer version of this article:

Land Hermit Crab Shell Guide

 

A hermit crab’s shell is his home and his protection from predators and dessication. Hermit crabs take up residence in discarded shells and can not make their own shell. When kept as pets it is important that you choose suitable shells for your hermit crab.

In semi-terrestrial hermit crabs a well-fitting shell is essential for maintaining low evaporation rates and carrying ample water. An appropriately sized shell in good condition allows invasion of inland environments offering more shade, food and fresh water for C. clypeatus studied on Curacao. Hermit crabs with broken, ill-fitting shells are restricted to the coast, must rely on drinking saltwater, and appear to be in relatively poor condition.[1]

Terrestrial hermit crabs show “shell facilitation”; that is, larger populations of crab generate, through wear, larger numbers of shells suitable for adult crabs. [2]

Hermit crab’s should be allowed to choose the shell they prefer from a selection of different sizes and types of shells. Natural shells are the best option. Painted shells should be avoided. Shells should not have jagged edges or holes in them.

Most species of hermit crabs will prefer a shell with a round opening. Coenobita compressus (Ecquadorian) prefers a shell with a D shaped opening.

Shells should be cleaned and boiled before offering to your hermit crabs. If you collected shells from the beach be sure the shells are EMPTY before bringing them home.

Hermit crabs can be very stubborn about changing shells but do not attempt to force a crab from it’s shell.

Contrary to common belief, a molt does not mandate a shell change! If the existing shell is roomy enough to allow for growth during a molt, the hermit crab may feel no need to change shells. Additionally, you will find some hermit crabs are chronic shell shoppers, always trying on something new.

Hermit crab shells are sold online by the size of opening. To determine the correct opening size measure the opening as shown here:

Measuring hermit crab shells

FAQ How do I choose suitable shells for my hermit crab?


Photos of common hermit crab shells:
Common Hermit Crab Shells

Are hermit crabs looking for lighter and larger shells?
The distribution, abundance and shell selection behavior of three species of hermit crabs
Land Hermit Crabs Use the Smell of Dead Conspecifics to Locate Shells
Coenobita violscens shell behavior
The Social Lives of Hermit Crabs

Check our collection of PDFs for more research documents about coenobita and sea shells.

References:
1. Wilde, 1973
2. Abrams 1978