HCA: Hermit Crab Association

I just wanted to add that the Zoo Med Hermit Crab Crunchies is also unsafe, but I didn't see it on the list. Any hope of adding it some people don't mistakenly buy it in the future?

Zoo Med Hermit Crab Crunchies (Land Crab Peanut Treat)
Ingredients: Peanut Meal, Whole Shelled Peanuts, Ground Lima Beans, Ground Wheat, Calcium Carbonate, Yeast Culture, Monocalcium Phosphate, Dicalcium Phosphate, Sodium chloride, Dried Spirulina Microalgae, Vitamin E Supplement, Folic Acid, L-Ascorbyl-2-Polyphosphate (stabilized Vitamin C), Mixed Tocopherols, Rosemary Extract, Ascorbic Acid, Citric Acid, Lecithin, Silicon Dioxide (carrier for liquid antioxidants), Choline Chloride, Vitamin A Supplement, Vitamin D3 Supplement, Menadione Sodium Bisulfite Complex, Calcium Pantothenate, Riboflavin Supplement, Niacin Supplement, Thiamine Hydrochloride, Pyridoxine Hydrochloride, D-Biotin, Vitamin B-12 Supplement, Manganese sulfate, Zinc sulfate, Ferrous Sulfate, Copper chloride, Ethylenediamine Dihydroiodide, Sodium Selenite

There are only three ingredients that keep a food on the unsafe list:

⁃ EQ or Ethoxyquin an antioxidant
⁃ Copper Sulfate
⁃ BHT, also known as butylhydroxytoluene

Peanut meal is fine, sodium chloride is salt, Menadione Sodium Bisulfite Complex is Vitamin K, and Ferrous Sulfate is Iron.

Whoah - weird... did some one just update the list? I just copied it this morning and it used to say:

The preservatives and harmful ingredients that everyone should be looking out for in commercial foods are artificial color, by-products, copper sulphate/sulfate, ethoxyquin, ferrous sulfate, foods containing "meal", magnesium oxide, menadione, propylene glycol, sodium chloride, zeolite, zinc oxide

Well, glad to see an update. I was wondering about the sodium chloride...

That's from Kili's nutrition guide, which was a personal article that was written by a member in 2008, but that was quoted so many times that it gets listed among the official HCA FAQs. We have a separate updated article on commercial foods here: http://hermitcrabassociation.com/phpBB/ ... 25&t=92555

Regarding Copper Sulfate:

The copper sulfate debate has been driving me crazy. I know it has been discussed in volumes elsewhere, but I could not find sourced material or biological process descriptions which supported either the benefit or damage caused by the consumption of copper sulfate by crustaceans. The reason this bothers me so much is that almost all commercial foods contain copper sulfate, and little option was available beside DIY shops on eBay or Etsy (i'm not bashing them; I do love the boutique style foods and snacks that only they make possible). But, at the back of my mind, I keep asking "How do I KNOW that I'm supplying my hermies with a completely nutritious diet?" furthermore "how do I know copper sulfate isn't found naturally in the ingredients of these DIY foods?". So, I set out to find my own answers.

First Stop: Contact 2 Hermit Crab Food suppliers!
When you need help, ask for it, right? The 2 commercial foods I'm most interested in are FMR Hermit Crab Food, and Hikari Crab Cuisine, so I sent them the following letter.

hi,
I am a new hermit crab owner, and I'm struggling to pick the best food for my hermit crabs. As I'm sure you know, the internet is full of people claiming that commercial crab food is full of poisonous chemicals. Yet very nearly all commercial foods contain copper sulfate, one of the "big four" terrible contaminants. But, deciding to go with a so called "natural" diet i'm: inadvertently denying them crucial nutrients, facing quality control issues since all "natural" food distributors are private etsy/ebay sellers, and may wind up giving the hermit crabs copper sulfate anyway via some natural/uncontrolled source.... Can you tell I worry a lot?. Anyway, all of this has wanting to ask you directly; why is copper sulfate in your FOOD NAME, and how have you tested its effects on Hermit Crabs?

Thank you for your time!

FMR has yet to respond.

Hikari responded:

Joe – Thank you for taking the time to contact us and for your interest in our products. Copper is an element that crabs use to remove waste from their circulatory system. It is depleted over time and must be replaced through nutrition. For this reason some has to be included in their diet in the right form and proper amount, without it they will perish over time. Of course our product has been extensively tested to be sure we meet the requirement amount and also that it won’t cause any negative impact to the shrimp. As a side note, our live fish division breeds shrimp that sell for more than $200 USD and this diet was developed for this part of our business.

The Hikari Customer Service Team

Not the most impressive response. But, It did give me some new information to work with. The Hikari food was designed for shrimp! So, what benefit do shrimp see from copper sulfate, and does that mean anything to my hermit crabs?

Second stop: Google "crustaceans copper sulfate"!
The first result appears to be a report suggesting that crustaceans have improved molting times, and bigger... e'hem!.. well, you can read the article here: http://scialert.net/fulltext/?doi=ijbc.2008.35.41

There is a ton of relevant information in that article. But, I kept searching, and ultimately found this posting that I think really summarizes the information quite pointedly:

Originally Posted by Veneer View Post
To be a stickler for terminology, shrimp don't have blood or a closed circulatory system as in vertebrates; instead, a fluid called hemolymph sloshes about within the body cavity. The oxygen-carrying molecule in their hemolymph is hemocyanin, a respiratory protein which binds oxygen using two copper atoms.

According to this paper, decapod crustaceans (like shrimp) need around 31.3 to 38.1 μg (1 μg = 1/1,000,000 of a gram) of copper per gram of body mass "to meet the requirements of both copper-associated enzymes and the copper bearing respiratory pigment haemocyanin".

The line between need and toxicity can be fine (source), but copper is an essential trace metal required for copper-dependent enzymes in energy production, pigmentation, and so on.

We should distinguish this dietary requirement from the effects of the cupric ion (Cu+2). This is copper's major toxic species -- doing much damage to crustacean gills by inhibiting osmoregulation -- and results when copper sulfate medications are added to water (source).

The entire exchange can be seen here: http://www.plantedtank.net/forums/88-sh ... r-why.html

That about seals the deal for me. People with iron deficiencies face trouble; so, if crustaceans use copper the same way we humans use iron, I expect they do in fact need "some" copper sulfate. How much... That is a new question. For my own purposes, I will continue to feed my hermies a combination of commercial food and boutique flavors. But, I will try to make sure they each get some commercial food each week.

I hope you find this information useful/insightful for your efforts in keeping hermit crabs. If you find any of this information inaccurate, and can source your information, please help us get that information rounded up and straightened out. It's for the good of our Hermit Crab friends.

Thank you. I found this very interesting.

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Providing them with a natural diet is not depriving them of crucial nutrients. Land hermit crabs are scavengers that feed on a wide variety of decaying organisms in the wild and no pellet or commercial food is ever going to offer or be equal to what they eat in the wild.

We recommend against commercial crab food for multiple reasons.

When you can easily and cheaply provide your crab with a great diet from your own kitchen, it's not necessary to give them processed, packaged foods.

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I haven't had time to read your links yet, but I'll offer my opinions after I've had the chance.



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