In an effort to simplify feeding for hermit crab owners we have put together a few printable hermit crab food guides.  These should be used in conjunction with our safe and unsafe lists.

*Nutritional Guide – What to Feed and Why Based on our Nutritional Table.

*Nutritional Table- Dietary Requirements with Sources

*Foraging Guide-Printable Resource

*Where to Buy Guide

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

If you have additions or corrections for any of these guides or other food lists please send them to crabstreetjournal@gmail.com As we don’t allow commenting due to spammers.

Additional food related articles:

Safe and Unsafe Wood-retired (See the Trees database below)
Edible Flowers – retired (See the Plants database below)
What Foods are Good and Bad? – retired (See the hermit crab Nutritional Table above)
Beneficial Foods Containing Zeaxanthin – (Also covered in the Nutritional Table above)
Learning to prepare food for your hermit crabs
Foods Containing Carotenids – (Also covered in the Nutritional Table above)
Color Enhancing Foods
Atypical Things Hermit Crabs Can Eat
Going Natural Beginner’s List
People Food for Hermit Crabs – retired
Growing Your Own Hermit Crab Food – retired
Hermit Crab Food Recipes
Should I Feed My Hermit Crab Meat – retired (Covered in The Power of Protein below and the Nutritional Table above)
The Power of Protein

This section is under construction! Keep checking back for more information!

Safe or Unsafe? Evaluating foraged flora and fauna for hermit crabs.

In our 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 item has been researched.

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 the LHCOS team 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. The team can offer you advice and opinions on these items but without research to back it up, we can’t speak in definites. I tried to collect some references here to get you started on your reading.

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 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 than we wanted I think!

Before foraging ANYTHING review this detailed list of poisonous plants so that you do not harm yourself or perhaps 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.

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

Our new approach is to group flora into one of four categories:

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

Toxicity was determined using 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/

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

Things to Consider:

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. Some plant families are used as natural insecticides. (See the Resources section below)

Some plants are bioaccumulators of toxic heavy metals. Cattails and Reeds are one example. [23] 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 our new searchable databases

Choose which database you want to search. 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.

Please note I’m still tweaking and cleaning up the databases so check back often!

Algae, Sea Vegetables, Moss and Lichens Database

Crops and Spices Databases

Animal Proteins and Invertebrates Database

Tree Database

Plants Database

A very detailed discussion about the new 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!

A curated list of books or guides related to edible plants and flowers- https://amzn.to/3IXjQp4

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