Learning to prepare food for your hermit crabs

Learning to prepare foods for your hermit crabs

Learning to prepare foods for your hermit crabs

Written by Julia Crab 2005
Coconuts: A Really Tough Nut to Crack

Yeah, these guys are tricky to open. But the fresh meat and milk inside are crab ambrosia. The best method for opening them is to employ an adult human male.

Barring access to one of those, note the three depressions at one end of the coconut. These are the coconut’s eyes. An icepick, a chisel, or a strong slot head screwdriver placed firmly in the center of one of the eyes, and bashed firmly and repeatedly by a hammer will eventually reward those with perseverance. A drill or jigsaw can also be employed by those who prefer not to soil their hands or break a nail with manual labor.

Once the eye is breached, pour out the milk, unless you enjoy cleaning up spills on the surrounding counter, floor and walls. You can put this in a small dish for the crabs to drink, or use it in a fruit and flower salad, or to moisten some puffed millet or crispbread. Believe it or not, you can even drink it yourself, in place of pina colada mix. Continue bashing, and wiggling the sharp tool a bit, and the coconut will split.

From there, it is a simple matter to scoop out the meat (with a butter knife or strong spoon). There will be a skin of brown coconut husk on the back of each piece of meat. Leave it on! This husk is very nutritious for the crabs and will not be immune to the kibbling power of the Ultimate Chopper. Break the coconut meat into chunks approximately 1 inch square, place in a freezer bag and freeze away! You can leave some shreds of meat inside one half of the shell (or whatever fraction you end up with) and put it in the tank for the equivalent of a crab cabaret – food and entertainment all in one package. Remove it within 48 hours, before the meat spoils.

Seaweed: Or, Getting Your Crabs to Eat their Sea Vegetables

It’s true. I did say that seaweed is a staple of coenobita diet. Then why won’t your crabs eat their sea vegetables?

Don’t feel bad. Mine won’t either, not without a lot of culinary sleight-of-hand.

Imagine your diet’s mainstay: meat and potatoes and its evil twin, McDonalds? Curry and rice? Mongolian barbeque? Now imagine what it would taste like if it had been dried out in the sun on a rock until it was hard and fragile, and then dumped in a trough nightly for you to eat. Sounds delicious, no? No.

I believe it is the same with the crabs. The palates of the seaweed we can offer them and the fresh stuff just washed up from offshore must be light years apart. Even the best dried organic seaweed and algae powder is like a freeze-dried C-Ration version of a meal from a four star Parisian restaurant. I have heard a few people say their crabs would eat dry toasted nori, and to be fair, some of that does disappear out of my crabs’ dry food dish on occasion, but there are other ways to persuade your crabs to eat seaweed.

Seaweed is an algae. The various large seaweeds are macroalgaes. Spirulina and blue-green algae are microalgaes. Despite the difference in size and appearance, these are all related plants and are all at the bottom of the food chain, which makes them the healthiest and purest sources of vitamins and minerals any one or creature can eat.

First and foremost: unless you live near a completely private, unpolluted beach, going to the seaside and getting some seaweed for your crabs is not the best idea. There is too much pollution on our recreational beaches these days for it to be a safe place to harvest seaweed.

Health food stores and grocery stores with Asian foods are the best sources for seaweed. A great on-line source is Maine Seaweed Company:


You can get by with just one variety of seaweed, but I feel it is best to have several that you can rotate through your crabs’ diet. The most essential algae of all is spirulina. It is the highest in beta carotene, and is also high in protein. A pound of it should sell for around $20. Many health food stores sell items like this in bulk, so that you can buy as much or as little as you need.

You have your spirulina. And blue-green algae, and kelp powder, and Irish moss powder. You’ve added some dried dulse, nori, bladderwrack and sea palm. Your crabs still sit next to the food dish and eat sand. Now what?

This is where the magic comes in.

Crabs, though cute, aren’t very bright. Like small children just learning to eat solid food, they can easily be fooled into ingesting things that are good for them.

I have four main methods of offering algaes.

1) Dry: Provide some dried, shredded seaweed and/or some of one or more algae powders in the dry food dish at all times. Dried seaweed, both the rubbery and crunchy kinds, chop up easily and willingly with a good knife technique. This is one job the Ultimate Chopper really isn’t good for.

2) Powder: I make a mixture of equal parts spirulina, Klamath blue-green algae, kelp powder and Irish moss powder. I sprinkle this on seafood, mix it in omelettes occasionally, and sometimes dust a honey and fruit dish lightly with it. It is very versatile, and nutrient rich for sick or pre-molting crabs. It is also vital that post-molting crabs have access to something like this, in order to retain or darken coloring. If one’s budget is tight, and only one can be obtained, spirulina is the clear winner. I feel it is the one most important algae in your crab pantry.

Each powder can also be used individually as well, for each has its own “special power,” as it were. In particular, Irish moss reputedly has anti-viral and anti-bacterial properties, as well as stress relieving qualities. It is an excellent choice to offer crabs suffering from post purchase stress. Mixing Irish moss in honey and feeding on a slice of banana or apple is the best way to get some healing into a scared and damaged rescue crab.

3) Kibble: Include some shredded dry seaweed with a seafood and grain kibble. Rice, tuna, dry red dulse and chanterelle mushroom is a quick example of how to use dry seaweed in a larger dish.

4) Reconstituted: This method is the closest my crabs have come to the real deal, seaweed fresh from the beach.

Heat a little ocean water in the microwave until steaming hot. Drop in dried seaweed, broken into bits that will fit in the water. Allow to soak until soft – this doesn’t take very long, and over-soaking the seaweed in hot water will leach the nutrients, so do it swiftly.

After the seaweed is soft, turn it out onto the cutting board and chop finely. I hold my breath as I can’t stand the smell. It’s become a habit now: chopping seaweed – holding breath. Even when I have a cold and can’t smell anything, I’m still holding my breath from force of habit.

From there, the seaweed can be offered in combination with other foods, as a base for another food, or, sprinkled with a little sea salt and calcium powder, as a dish on its own.

Crabs Need Cholesterol: An Egg a Week

Hermits, like every other creature, require some cholesterol in their diet in order to be healthy. I offer my crabs egg once a week to ten days. The best thing about making egg for crabs is that you actually want to leave bits of shell in the food, so you don’t have to work so hard preparing it.

Factory hen eggs are very bad for your crabs. These chickens are sickly, fed a poor diet, force fed antibiotics and hormones. The eggs from these chickens are inferior and tainted, down to the calcium in the shell itself. Forget the crabs, they’re bad for you! And they don’t really taste nice, once you’ve tried the alternative.

Free range, organic eggs are the best way to go, if you can’t grow your own. They taste better and are better for you and your crabs.

That said, there are several methods of offering eggs to your crabs. In an ideal world, they should be raw. I don’t recommend this. The humid, warm environment of a crabitat is perfect to grow bacteria such as salmonella and e. coli, which do not necessarily require a living host to thrive. Egg and raw meat, while more in keeping with what the crabs would eat in the wild, need to be handled carefully, and cleaned up after promptly.

A good way to simulate raw egg is to soft boil an egg in distilled water. Then crack it open and tear it apart into sections for the crabs in the main tank and any in ISO. Be certain to preserve the yolk, still runny, in the egg sections in the food dish. I often put seaweed salad or something else in the yolk for them to enjoy.

Egg can also be scrambled, with the addition of spirulina powder or other seaweed, seafood, grated vegetable, cod liver or flax oil, grains or seed meals, or other foods. Pulverize some of the egg shell and be sure to include it as well.

Egg can also be hard boiled and offered with a little sea salt, or chopped into some other food.

The Goodness of Grain

Grains are good for crabs as they are high in calcium and other nutrients. Natural, whole grains are preferable to processed refined grains. Brown rice instead of white, for example. Crabs can eat dry grain, but I have found that mine eat better when I have soaked it for a short time in steaming hot salt water, just enough to soften the outer layer of the grain. Putting larger grains through the Ultimate Chopper with other food items afterwards will reduce it in size and make it more attractive to eat.

In the wild, crabs eat a wide variety of grass seeds, or grains. C. compressus is even considered an agricultural pest on rice crops.

Salt: Bring it On

Salt is required by crabs in order to retain proper osmotic levels in their shell water, and to molt successfully. There is absolutely no problem with sprinkling a tiny amount of sea salt on just about anything you want your crabs to eat. The salt will make many foods more attractive to them. Remember that the majority of what they find in the wild has been dead or rotting on the beach and is likely covered with salt.

When purchasing sea salt, like everything, be certain to inspect the label for any hint of an additive or caking agent. It needs to be pure sea salt.

Citrus: The Truth is Sweet
Somehow, somewhere, someone heard that citrus peel contains volatile oils that act as insect repellents and insecticides, added two and two together, and came up with seven; namely, that crabs, being arthropods (and related to insects), cannot tolerate citrus in their diet.


Citrus fruits are tropical and sub-tropical. Coenobita, coincidentally, are tropical and sub-tropical. Hermit crabs are constantly exposed to citrus in their native environment. They can, and will eat citrus fruit.

It is not bad for them. On the contrary, the addition of citrus to your crabs’ diet can be extremely beneficial. The trick is in knowing which kind of citrus, and how to offer it.

Crabs prefer sweet citrus to sour; tangerines over grapefruit. They will pick at the flesh of the fruit, but actually prefer to eat the pulp and membranes between the fruit sections and the fruit and skin. This substance collectively is known as hesperidin, and is full of dozens of phytonutrients. These phytonutrients are compounds, such as beta carotene, that have nutritional value, but it is uncertain how much. They have not had much study. Some are said to be good for arterial disease, others for other things. I am doing research on hesperidin currently. I will be writing an article on its value in the future.

Because of the scavenging nature of crabs, it is entirely possible that these phytonutrients are very important to their health in ways we can’t even imagine. So the addition of citrus fruits to the diet of a crab is to their benefit.

The best method I have found for preparing citrus is as follows:

Put the fruit on the counter and leave it until it starts to wrinkle up a bit, and the skin pulls off the flesh. The limonene and other possibly irritating compounds in the skin will have begun to break down at this point and will no longer be an issue (if, in fact, they ever were). When it is just getting to the point where you wouldn’t eat it yourself, cut off a section, skin and all, and put it in the food dish. Pull up a corner of the fruit so the crabs can get to the pith inside the skin. For good measure, pull out all the fiber from the center section and add it to the dish as well.

I have found that my crabs will eat the hesperidin and pick at the fruit. They ignore the peel completely.

In Conclusion

Once you’ve mastered these basic techniques, you’ll be able to create a varied and extensive menu for your crabs. They may not be able to tell you in so many words, but the increase in molting frequency, and the darkening of their color, will say it all.

Bon appetit!


Now that you’ve decided to provide your hermits with a gourmet diet, you’ll need to know how to handle various foods to make them attractive to your crabs. In this installment of the Epicurean Hermit, I will address various techniques for preparing gourmet hermit food, and the tools that you might want to add to your kitchen to assist you in preparing them.

The tools I’m going to address here are the ones that I use myself in my own kitchen. These aren’t the only tools that can be used, however. You can make all the crab foods I mention in this and future installments with just a good sharp knife and a cutting board. However, these tools make preparation easier and faster. Where I am aware of possible substitutions, I will mention them as well.

Ultimate Chopper

I purchased an Ultimate Chopper when I saw one on television, to make baby food with. Of course, it never got used for that, as it was easier to buy jars of organic baby food, and now my daughter is too old to eat puree. I tried this item on our regular meals, but it has a tendency to reduce everything put in it to powder or mush. This doesn’t make it attractive as an adult human food processor, but it makes wonderful crab kibble. Unlike a regular food processor, it only handles small amounts of food at a time, and is easy to clean and assemble. I have been told that this item can also be found at Wal-Mart.

The Ultimate Chopper chops everything up into tiny bits the perfect size for crab maxillipeds to handle, from micro to jumbo. Your little crabs will be grateful for the help, and the bigger ones won’t complain about how easy it is to eat food prepared by this method.

If an Ultimate Chopper is not available to you, a regular food processor can be substituted. Or, lots of fine chopping and blending with your trusty sharp knife.

Mortar and Pestle
When grinding sources of calcium, pulverizing nuts and seeds, or breaking down dried seaweed or flowers, a mortar and pestle is invaluable. Marble or smooth granite are the best options. You will want to find one that is smooth, and not porous. Porous ones will be harder to clean, and harder to use. I bought mine on line at Temple of Thai. I have been told that these can be found at places like ‘Big Lots!’ for much less.

If a mortar and pestle is not something you are interested in investing in, putting the items you want to crush in a heavy duty freezer bag, wrapping it with a dishtowel, and beating it with a rolling pin, meat mallet, or hammer will also do the trick, though the resultant powder might not be as finely mashed, and you won’t have the fine control over the end result you will have with the mortar and pestle. But so long as your smaller crabs can eat the end result of your smashing, it’s not important to make it uniform.

Vegetable Grater

A normal sized kitchen grater will have holes a bit too large to use for crab food, for the most part. I happened to find a two and a half inch tall, scaled down version of this kitchen standby at Cost Plus World Market. It has the same faces as the regular kitchen grater, but is much smaller, making finer grated items. This item is optional, if you have an Ultimate Chopper or food processor, but I really like mine.


As I mentioned in the Introduction, stainless steel or glass/ceramic/pyrex are the only safe options for cooking crab food. Most crab food does not require cooking; it’s just fun to experiment once in a while with culinary masterpieces the crabs might enjoy.

Even for boiling sponges, dishes, and shells, one should avoid all other types of cookware.

Bon appetit!