Foods Rich in Minerals Crabs Require

I’ve been doing a lot of reading of several research papers I recently acquired. Basically, I’ve been taking a crash course in crustacean biology. One of the recurring themes of all the papers that address molting is that crabs require copper, zinc and calcium in their diets in order to perform molting successfully, and to remain healthy.

Commercial foods do add these minerals, but one of the minerals used most often to boost copper content of a food, copper sulfate, is part of an extremely powerful organic gardening fungicide/insecticide, Bordeaux mixture (see http://extoxnet.orst.edu/pips/coppersu.htm for the data sheet on this substance). Copper sulfate is a particularly poisonous form of the required metal, so I avoid foods that add that form of copper. My feeling on the addition of any laboratory produced or mined minerals is that they are inferior in all ways to minerals acquired through diet.

What is a crabber then to do? I prefer to offer my crabs organic, human-grade foods. I looked around a bit to find a list of crab-friendly foods that can be offered to boost calcium, zinc, and copper, respectively.

Copper-Rich Foods:

Cereals, especially wheat and rye
Chickpeas and other legumes such as beans
Fish
Liver
Meat
Most nuts (especially brazil and cashew nuts, pecans and peanuts)
Oysters
Peaches
Raisins
Seeds (especially poppy and sunflower)

Zinc Rich Foods:

Corn
Cucumber
Egg yolk
Haddock
Lamb
Legumes
Lentils
Lettuce
Nuts
Olive Oil
Peas
Pork chops
Sardines
Spinach
Tuna
Whole grains


Calcium-Rich Foods

Broccoli
Canned salmon with bones
Dried beans and peas
Greens
Sardines

However, many of the leafy green vegetables contain enzymes called oxalates which can bind with calcium, preventing its absorption. To inactivate these enzymes, the greens must be cooked before serving. Be sure to use dechlorinated water!

And, the top food to feed one’s crabs for these minerals and other absolutely necessary nutrients, is sea vegetable, the macroalgaes (seaweed) and the microalgaes (spirulina, etc.).

Kerie

 

kali,
Thank you so very much for that info, especially for the research you have done to benefit our hermies!!

 

Keri,
Thanks for the great information! I was searching for some spirulina for my crabs, but most of it has the dreaded ETHO in it. I came across this one and wondered what you thought of it. They claim it is 95% pure spirulina.

http://www.jehmco.com/PRODUCTS_/FISH_FOODS_/Flake_Foods/Pure_Spirulina_Flake/pure_spirulina_flake.html

 

Hi,

I personally would avoid any sea vegetables meant for pets. Even if they don't list EQ on the label, it only means the pet food manufacturer didn't add it themselves after making their food for sale. Sea foods meant for pet consumption almost invariably have EQ added to them before being shipped to pet food manufacturers, from what I have been told -- I have not gone and verified this for myself, though I should.

Also, I would really wonder what the other 5% of that fish flake was. Is it vitamins/minerals they had to add because they removed too much in over-processing it? Is it caking agent?

I strongly recommend that people interested in their crabs' health switch to human-grade organic products. EQ is not allowed to be added to human foods. Spirulina and other sea vegetables that are good for your crabs can be obtained at most health food stores, often in bulk so that you can take as much or as little as you need. If you don't have access to a health food store in your community, I found a relatively inexpensive 1 pound jar of organic spirulina at:

http://www.stakich.com/sfolder/spirulina.htm?src=overture&ovmkt=TIN03IM5B4912QHM574O4CEEUO&OVRAW=spirulina&OVKEY=spirulina&OVMTC=standard

They list it for $20 with a flat $4 shipping. Or, put "spirulina" in your web browser and shop around a bit.

Crabs like variety in their diet, and prefer to eat foods they have not eaten recently over foods that they see every day. So it behooves you to give them more than one source of algae in their diet -- sea weeds and spirulina are all algaes. Another way to get them to eat their spirulina powder is to disguise it in other foods. I slip seaweeds and other nutritious items like flax seed meal into their scrambled eggs, or their honey and banana.

Kerie

 

I just now found some research that states that coenobita can eat starchy foods, i.e., potatoes. These are also rich in copper and other trace minerals.

Kerie

 

Keri,
I agree with you about variety. My crabs have gone 3 weeks without getting the same combination of foods twice I see them eating everyday. I make sure that they at least have a green, purple or red seaweed with each meal along with some form of calcium.

BTW, I wanted to ask what you think about Freeze Dried Mealworms? I have read that they are a little more difficult for reptiles to digest...do you think this holds true with the crabs? I have given them to my crabs along with Freeze Dried Crickets and they love them. Oh, and what about Bladderwrack?

I really have to stop and marvel at my late Grandmother. Everything she ate was organic. She raised her own chickens for the meat and eggs grew her own fruits and veges and always had raw pure honey and natural peanut butter at her house. I remember thinking she was nuts when I was a small kid. Now it makes me tremedously sad to realize how intelligent she was and how I lost out on learning a lot of very important things from her.

 

Hi, Wendy,

Crabs' digestion is really different from vertebrates' digestion, so comparing whether a lizard and a crab can digest the same foods is probably a moot point. I'm coming to the realization that if it is natural food (not full of weird additives and sugars) the crabs can tell if they want to eat it or not, and will avoid foods that they find no nutritional value in. The sugars, MSG and garbage skew their perceptions of the food, just like they do ours, and make them more attractive, even though they are worse for the animals.

So, if you offer your crabs an insect or dead animal, and it eats it, it probably enjoyed it and will benefit from its digestion.

Kerie

 

I forgot to answer about the bladderwrack.

Bladderwrack is a wonderful food -- for your crabs AND for you. I did an article on it at CSJ, here's the link:

http://www.crabstreetjournal.com/modules.php?name=Forums&file=viewtopic&t=252

And, by the way, my crabs ignored the potatoes completely... I asked the researcher about it, and she said in order to get her crabs to be interested in them, she had to add some margarine and sea salt. The skins, particularly, are good for them.

BUT they shouldn't have any part of the potato that is green, as that is poisonous, potatoes being part of the nightshade family. So, no green spots, no eyes, no leaves.

 

Deri,
I really appreciate your hard work with the research for the crabs diet. I need to get to the health food store soon.
Thank you again.

 

Kerie, excellent thread, thanks for all the wonderful tips!

have you tried sweet potato? My crabs LOVE it.