CSJ’s Ultimate Guide to Feeding Your Hermit Crabs

The basics of hermit crab feeding

Most commercial hermit crab foods contain ethoxyquin and/or copper sulfate. Fish meal typically contains hidden ethoxyquin that is not required to be listed. Both ethoxyquin and copper sulfate are toxic to invertebrates.

There are many things in your kitchen that your hermit crabs can eat also. The collages below made by Amber Miner show some of the more common food items you can safely feed to your hermit crabs.

Here is a printable safe food list for feeding your hermit crabs:

Safe Food List-A Generous List of Foods Your Hermit Crabs Can Safely Eat

Hermit crabs require a nutritionally complete diet for proper molting, growth and to prevent cannibalism.

Understanding a hermit crab’s nutritional needs is the first step to creating a feeding plan.

• Nutritional Guide – What to Feed and Why Based on our Nutritional Table.
• Nutritional Table- Dietary Requirements with Sources

Foraged foods for hermit crabs

Hermit crabs need and enjoy food items that you can safely forage Hermit Crab Food Foraging List

Foraging Guide-Printable Resource

Additional hermit crab food related articles:

Beneficial Foods for Hermit Crabs Containing Zeaxanthin – (Also covered in the Nutritional Table above)
Learning to prepare food for your hermit crabs
Foods Containing Carotenids for Hermit Crabs – (Also covered in the Nutritional Table above)
Foods that will enhance your hermit crabs color
Going Natural Beginner’s List for Feeding Hermit Crabs
Hermit Crab Food Recipes
The Power of Protein in the Hermit Crab’s Diet

Photos of common hermit crab foods

Created by Amber Miner and authorized for use by The Crab Street Journal. All Rights Reserved.

What foraged foods are safe or unsafe for hermit crabs to eat?

Evaluating foraged flora and fauna for hermit crabs.

This guide applies to foraged items intended for food or decor, NOT as a substrate.

In my ongoing effort to back our recommendations with science, we are revamping our safe/unsafe flora and fauna lists. This is by no means an exhaustive, international list but every single item has been researched by me (Stacy Griffith) and Stacey May.

In our early days there was a lack of research regarding hermit crabs so our only option was to rely on food lists intended for other animals (birds, turtles, mammals). So in the interest of being as safe as possible that is what we did.

Today, crustaceans are researched more often and, while we still do not have studies devoted to food toxicity specifically for land hermit crabs, we do have a better understanding of biological function and there is data available regarding invertebrates and other crustaceans from which we can gain information.

This new list has been created with a specific audience in mind – hermit crab keepers who want to stray from the beaten path to try less common foods. There is nothing wrong with that desire but it is impossible for me to have such a depth of knowledge of every plant or tree that exists to be able to speak to its toxicity. So if you are in this group, you will be required to do some reading and make your own informed decisions about whether or not feeding something questionable is worth the risk. I can offer you advice and opinions on these items but without research to back it up, I can’t speak in definites. I collected some references to get you started on your reading. Scroll to the bottom for those.

Now, if you are in the other crowd, who prefers to stick with our generous list of known safe plants, trees etc know that list is not going away.

If you are looking for a hermit crab feeding pocket guide I highly recommend Fresh & Foraged Foods for Land Hermit Crabs from MyHungryHermit.com The author, Stacey May and I collaborated on our food projects. We both know far more about plants now than we ever wanted!

Protect yourself when foraging

Before heading out to forage for your hermit crabs review this detailed list of poisonous plants so that you do not harm yourself or your dog or cat. For example, the Manchineel tree is considered to be the most toxic tree of all yet hermit crabs in Curacao were seen eating from it. [1]

Eat The Weeds is another great resource.

Protect the environment when foraging

Additionally, is it vitally important that you forage and harvest in an ethical manner and in accordance with all state and local laws.

Flora and fauna is now grouped in categories for our purposes

Safe	No reported toxicity to any animal (including humans)
Mixed	Some parts indicate toxicity to at least one animal, while other parts are safe. Toxicity in humans or mammals does not guarantee toxicity in crustaceans.
Unknown	Most or all of the parts are toxic to animals or humans but no data exists on toxicity to crustaceans.
Caution	Toxicity to crustaceans has been demonstrated in concentrated extractions. This does not necessarily indicate toxicity in the natural state as it would be consumed by hermit crabs. This is especially true of of the items that indicate toxicity at HIGH CONCENTRATIONS. These items are safe in their natural state in our opinion but because there is no research to back that opinion these items will remain in the CAUTION category. THESE ITEMS ARE USE AT YOUR OWN RISK.
Unsafe	Demonstrated toxicity to insects or crustaceans in very low concentrations or natural state

My determination of toxicity to hermit crabs was based on tests that utilized the Brine Shrimp Lethality Assay.

Brine shrimp lethality bioassay is a simple, high throughput cytotoxicity test of bioactive chemicals. It is based on the killing ability of test compounds on a simple zoological organism-brine shrimp (Artemia salina).[1] This assay was first proposed by Michael et al., and further developed by several groups.[2,3,4] The brine shrimp lethality bioassay is widely used in the evaluation of toxicity of heavy metals, pesticides, medicines especially natural plant extracts and etc.[5,6] It’s a preliminary toxicity screen for further experiments on mammalian animal models.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3960796/

Things to consider when evaluating toxicity to hermit crabs

Demonstrated non toxicity or toxicity in another species or class of animal does not necessarily prove or negate the same being true of our land hermit crabs. A land dwelling crustacean may not develop the same ability to safely store toxins as an aquatic, freshwater crayfish. This protection would have developed slowly over time in the crayfish. A land hermit crab is not exposed to the same environmental threats as a water dweller. Much of the research we rely on is based on aquatic species so again we must use our best judgement.

An example…

Another poisonous lichen, Parmelia molliuscula (also known as “ground lichen”), was determined to be the cause of death for 300 elk in Wyoming in 2004. Visiting elk from Colorado* ate this lichen, which caused tissue decay and eventual death. The native elk were not affected, simply because their immune systems were already equipped to deal with this toxic lichen. This is another example of wildlife and plant life evolving with each other.

https://www.fs.fed.us/wildflowers/beauty/lichens/didyouknow.shtml?fbclid=IwAR2_nkmnxr8OCeAoiXKJsX-rDHJtgrN-m_OMzSzbc5rj7KKB6yGSsYHYcP8 *My emphasis

Some plant families are toxic to humans, livestock, fish, dogs, cats but that doesn’t mean they are automatically toxic to invertebrates. Some plant families are used as natural insecticides. If the concentrated extract of the plant is used as the insecticide the plant in its natural state may not be strong enough to be harmful. There are so many variables to consider.

Some plants are bioaccumulators of toxic heavy metals. Cattails and Reeds are one example. [23] Knowing where to safely forage is equally important. Plants growing next to crops are exposed to insecticide sprays and runoff.

Some plants are excellent for phytoremediation of contaminated soil. https://land8.com/5-best-plants-for-phytoremediation/ and http://www.cpeo.org/techtree/ttdescript/phytrem.htm

Bioaccumulation occurs when an organism absorbs a toxic substance at a rate greater than that at which the substance is eliminated.

Is it worth the risk?

While it can be fun to feed something new and weird the first thing to consider is this: Is the payoff worth the risk? In other words, what is the perceived benefit of feeding this item and can it be safely obtained through another, known safe, food item?

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How to use the searchable databases

Choose which database you want to search. Flora and fauna are grouped into several databases.

Enter one search term. Using the scientific name for plants, trees, crops will make searching easier. Some plants have a dozen ‘common names’ which vary by country.

If you want to see everything unsafe in the particular database, use “Unsafe” in the Category search box.

Algae, Sea Vegetables, Moss and Lichens Database

Crops and Spices Databases

Animal Proteins and Invertebrates Database

Tree Database

Plants Database

Hermit Crab Food Database Usage Policy

The Crab Street Journal Hermit Crab Food Database is a valuable resource created to support the care and well-being of hermit crabs.

You are welcome to link to or reference the hermit crab food database for educational, personal, or non-commercial use, provided proper credit is given to The Crab Street Journal with a direct link to the original database page.

Reproduction, redistribution, or modification of the hermit crab food database content, in whole or in part, is strictly prohibited without prior written consent. This includes copying data, screenshots, or compiling information for use in other databases or publications.

The hermit crab food database content may not be used for commercial purposes or in the development, training, or enhancement of AI models or automated tools without explicit permission.

If you wish to use the hermit crab food database beyond linking or referencing, please submit a request via our Acceptable Use Policy.

A very detailed discussion about the new hermit crab food list and databases

Resources:

This chart demonstrates the frequency of plant families with insecticidal activity. Lamiaceae family having the most plants with insecticidal activity.

The insecticidal activity of 28 essential oils again Sitophilus zeamais (maize weevil) adults.

If you want a basic overview of Toxic Principles check out Toxicology on Brainscape

http://eattheweeds.com

The plant database is huge so we can’t possibly cover every single one.

Need a visual? Use the USDA Plant Image Database!

CSJ recommended books on Amazon

AS AN AMAZON ASSOCIATE, I EARN FROM QUALIFYING PURCHASES. I ONLY ENDORSE THINGS I’VE PERSONALLY USED OR COME HIGHLY RECOMMENDED BY TRUSTED PEERS. OUR AFFILIATE DISCLOSURE POLICY CONTAINS MORE INFORMATION

References

1. On the Ecology of Coenobita Clypeatus in Curaçao With reference to reproduction, water economy and osmoregulation in terrestrial hermit crabs Erik Wilde 1973
2. Arsenic: Medical and Biologic Effects of Environmental Pollutants. https://www.ncbi.nlm.nih.gov/books/NBK231025/
3. Cyanogenesis in plants and arthropods -Mika Zagrobelny, Søren Bak, Birger Lindberg Møller
4. https://en.wikipedia.org/wiki/Cyclobuxine
5. Toxic essential oils. Part V: Behaviour modulating and toxic properties of thujones and thujone-containing essential oils of Salvia officinalis L., Artemisia absinthium L., Thuja occidentalis L. and Tanacetum vulgare L.
6. Extractives and their physically modified derivatives such as tinctures, concretes, absolutes, essential oils, oleoresins, terpenes, terpene-free fractions, distillates, residues, etc., obtained from Cupressus sempervirens, Pinaceae.-https://echa.europa.eu/registration-dossier/-/registered-dossier/16636/6/2/4
7. Effects of Essential Oils from Eucalyptus globulus Leaves on Soil Organisms Involved in Leaf Degradation Carla Martins, Tiago Natal-da-Luz, José Paulo Sousa,  Maria José Gonçalves,  Lígia Salgueiro,  and Cristina Canhoto – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3618273/^/
8. Chapter 12 The Impacts of Selected Natural Plant Chemicals on Terrestrial Invertebrates Neal Sorokin(*ü ) and Jeanette Whitaker
9. The comparative toxicity to soil invertebrates of natural chemicals and their synthetic analogues J. Whitakera*, J.S. Chaplowa, E. Pottera, W.A. Scotta, S. Hopkinb, M. Harmanc, I. Sims and N. Sorokine
10. https://csuvth.colostate.edu/poisonous_plants/Plants/Details/68
11. Toxicity and antifeedant activity of lichen compounds against the polyphagous herbivorous insect spodoptera littoralis Robertemmerich, Ingrid Giez, Otto L. Lange And Peter Proksch
12. Toxic effects of microcystins in the hepatopancreas of the estuarine crab Chasmagnathus granulatus (Decapoda, Grapsidae) G.L.L. Pinho , C. Moura da Rosa , J.S. Yunes , C.M. Luquet , A. Bianchini , J.M. Monserrat
13. Impact of a toxic and a non-toxic strain of Microcystis aeruginosa on the crayfish Procambarus clarkii V Vasconcelos, S Oliveira, F O Teles
14. https://en.wikipedia.org/wiki/Vulpinic_acid
15. Medicinal Plants from North and Central America and the Caribbean Considered Toxic for Humans: The Other Side of the Coin https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5688365/pdf/ECAM2017-9439868.pdf
16. Biological screening of selected Pacific Northwest forest plants using the brine shrimp (Artemia salina) toxicity bioassay https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4842189/pdf/40064_2016_Article_2145.pdf
17. Essential Oils: Extraction, Bioactivities, and Their Uses for Food Preservation https://onlinelibrary.wiley.com/doi/full/10.1111/1750-3841.12492
18. Toxicity and Risk of Plant-Produced Alkaloids to Daphnia magna. DOI:10.21203/rs.3.rs-105938/v1
19. https://www.sciencedirect.com/topics/chemistry/bioaccumulation#:~:text=Bioaccumulation%20is%20a%20process%20of,dietary%20intake%20(trophic%20transfer).
20. https://www.fs.fed.us/wildflowers/beauty/lichens/didyouknow.shtml?fbclid=IwAR2_nkmnxr8OCeAoiXKJsX-rDHJtgrN-m_OMzSzbc5rj7KKB6yGSsYHYcP8
21. https://en.wikipedia.org/wiki/Apiaceae
22. https://en.wikipedia.org/wiki/Solanaceae
23. Agnieszka Klink, Aurelia Macioł, Magdalena Wisłocka, Józef Krawczyk, Metal accumulation and distribution in the organs of Typha latifolia L. (cattail) and their potential use in bioindication, Limnologica, Volume 43, Issue 3, 2013, Pages 164-168, ISSN 0075-9511, https://doi.org/10.1016/j.limno.2012.08.012. (https://www.sciencedirect.com/science/article/pii/S0075951112000680)
24. https://www.sciencedirect.com/science/article/pii/B9780120887651500105
25. Sirelkhatim Balla Elhardallou , 2011. Cytotoxicity and Biological Activity of Selected Sudanese Medicinal Plants. Research Journal of Medicinal Plants, 5: 201-229. DOI:10.3923/rjmp.2011.201.229 URL:https://scialert.net/abstract/?doi=rjmp.2011.201.229
26. Click to access copper-sulfate-toxic.pdf
27. Acute and Chronic Toxicity of Copper to Four Species of Daphnia Authors : Robert W. Winner and Michael P. Farrell
28. The effects of Copper and Zinc on survival, growth and reproduction of the cladoceran Daphnia longispina: introducing new data in an “old” issue Celso Martins , Fátima T Jesus , António J A Nogueira 
29. Chronic toxicity of dietary copper to Daphnia magna K.A.C.De Schamphelaere^aI.Forrez^aK.Dierckens^bP.Sorgeloos^bC.R.Janssen^a
30. Ethoxyquin: a feed additive that poses a risk for aquatic life Sophia Egloff , Constanze Pietsch
31. http://sitem.herts.ac.uk/aeru/ppdb/en/Reports/280.htm
32. https://projects.ncsu.edu/cals/plantbiology/ncsc/poisonous/families.htm
33. Insecticidal and antifungal chemicals produced by plants: a review DOI: 10.1007/s10311-012-0359-1
34. Plant Allelochemicals as Sources of Insecticides – Gajger, Dar https://doi.org/10.3390/insects12030189
35. Walking Sideways: The Remarkable World of Crabs – Judith Weis