What Do Crabs Eat and How to Feed Them?

What Do Crabs Eat and How to Feed Them

Owning a pet land crab or aquatic crab can be a very worthwhile and unique experience. So, if you are looking to keep them as pets, it is important to do research on how to take care of them and how to feed them.

Generally, crabs are omnivorous and opportunistic feeders. They will eat just about anything they can get their claws on. It can be detritus, animals, and plants, either living or decomposing.

I am saying “generally” because they’re more than 4500 different species of crabs in the world and about 50 species that are heavily traded in the aquarium hobby. Each species has its own feeding requirements. In addition, their feeding preference may change depending on the age and the molting cycle

In this article, I will highlight the various food sources available to crabs for consumption, and how often they should be fed in captivity.

What Do Crabs Eat in The Wild?

Most crabs are foraging omnivores. They will eat plant and animal matter that they come across. Basically, it means that they will eat anything left unattended on the ground, as they are scavengers.

At the same time, certain species and even families show tendencies towards a more specialized diet.

For example, Portunid crabs are reported as being mainly carnivorous, feeding on many organisms, particularly on slow-moving invertebrates such as molluscs, snails, slugs, worms and crustaceans (including other crabs up to their own size).

Some terrestrial crabs of Sesama family are common herbivores. They feed on a variety of plant materials as well as on decaying organic matter, like: leaves, plants, flowers, belowground rhizomes, fruits, vegetables, barks, seeds, grains, etc.

What Do Crabs Eat In The Aquarium?

A simple fact most crabs are not fussy eaters by nature does not mean that we can give them whatever we like or that we should not care about their diet.

This approach will only lead to diseases and problems with their exoskeleton.

So, if we want to give them the best life possible, we need to provide them with a well-balanced diet. By doing so, crabs will get all necessary microelements, vitamins, and minerals that are needed for their body to function correctly.

That is why it is very important to understand that they need to have a varied diet of: 

  • Vegetables and Fruits
  • Protein
  • Calcium

Terrestrial, semi-terrestrial, and aquatic (freshwater and marine) crabs should be fed differently. We have to understand some limitations.

For example, in the aquarium, I would avoid all citrus fruits, tomatoes, avocado, etc. These foods contain a lot of sugar and can cause a bacterial bloom in your tank. As a result, it can also lead to depletion of oxygen and/or even lower pH in your tank. Another problem is that most of the fruits are too messy.

It can be even worse in marine tanks. So I would never recommend using fruits in marine tanks.

At the same time, you will not have such problems with terrestrial and semi-terrestrial crabs in paludarium and terrarium setups.

You can also read my article “Difference between Aquarium, Terrarium, Riparium, and Paludarium?”.

Recommended Food for Crabs


  • Asparagus     
  • Alfalfa
  • Basil   
  • Broccoli         
  • Beet   
  • Carrots           
  • Clover
  • Corn   
  • Cabbage of all sorts 
  • Cucumber     
  • Cauliflower   
  • Green beans 
  • Green pea     
  • Leeks
  • Lettuce           
  • Moss 
  • Nettle
  • Oats (soaked and mashed) 
  • Pumpkin
  • Peas
  • Parsnip         
  • Plantain (broadleaf)   
  • Pepper (only sweet)
  • Swede
  • Sprouts
  • Turnios
  • Watercress
  • Zucchini


A variety of fruits your crabs will enjoy.

  • Apples
  • Apricot
  • Avocado                   
  • Banana                     
  • Blackberries
  • Blueberries               
  • Butternut squash                   
  • Cherry           
  • Coconut                                           
  • Dragon fruit
  • Grape and Raisins               
  • Mango
  • Melon
  • Nectarines
  • Olives
  • Papaya
  • Pear
  • Plum
  • Peach
  • Physalis
  • Raspberry
  • Strawberry
  • Sharon fruit
  • Satsuma
  • Tangerine
  • Watermelon

Note: Most fruits need to be peeled (even grapes, plums, etc.).  You can also cut them into small pieces so the crabs can eat them easily.

Protein Food

Generally, crabs need a lot of protein to grow and in the absence of food, they can start cannibalizing fast.

Based on different experiments and observations, in many crab species, the maximum growth can be achieved in the 20-30% protein diet.

Keep in mind that there are two types of protein:

  • animal-based,
  • vegetable-based.

Even though, in terms of components, we will not see a big difference between animal and plant proteins, the ratio of amino acids is different. That is why crabs need all types of protein. Diversity is very important!

The following are suitable food items for your pet crab:

  • Beef (raw, or boiled)
  • Chicken (raw or boiled)
  • Pork (raw or boiled)
  • Fish (raw or boiled)
  • Shrimp (raw or boiled)
  • Brine shrimp
  • Blackworms
  • Bloodworms
  • Grindal worms
  • Cockroaches
  • Crickets
  • Krill (freeze-dried)
  • Snails (crushed)
  • Mosquito larvae
  • Eggs (including shells)


Calcium is super important for any crab species because this is the main component of their exoskeleton (shell). For example, their exoskeleton comprises up to 50% of dry weight and is mineralized with calcium carbonates and magnesium.

A calcium deficiency can cause weakness in the shell and when this happens, the crab becomes susceptible to diseases, heat, and dehydration (in terrestrial crab species).

Calcium can be found in such products as:

  • Kale,
  • Broccoli,
  • spinach,
  • Seaweed,
  • Figs,
  • Nuts,
  • Cuttlebones,
  • Eggshells,
  • Wonder shells,
  • Oyster shells,
  • Seeds,
  • Insects (carapace),
  • Mollusks (shells), etc.

Cuttlefish bone should be in the tank all the time. 


Be very careful with plants in crab tanks.

I’d say that there are only a few species that are safe to keep in planted tanks (for example, Pom Pom Crabs, Vampire crabs, Thai Micro Crabs). So, do your research beforehand!

In all other cases, there is a huge risk that plants will become their delicacy. Unfortunately, many crab species will eat, cut, and uproot any plant in the tank.

Therefore, unless you are ready to buy some cheap plants you are willing to lose, it will be better to focus on floating plants or fake plants.

Commercial Diets

In captivity, the crab’s diet should also include a balanced commercial food supplement with a variety of fresh foods and treats.

As with all crustaceans, ideal food sources include popular dry pellet foods and frozen foods. These are commercially prepared, high-quality foods that contain high amounts of protein & vitamins.

Good examples of these are (links to check the price on Amazon):

Crabs may really like salty, fatty, or sugary snacks such as chips, and sweetened cereal but these should be avoided.

How Often and How Much Should You Feed Crabs?

In general, most adult crab species do quite well on one feeding per two days. However, some owners prefer to feed them daily to prevent them from getting hungry and picking on tankmates.

However, young crabs should be fed every day. They grow fast and require frequent feeding. The good thing though is that young crabs will eat the same meals as adult crabs.

The amount of food required for each crab is up to 5-10% of its weight.

Of course, nobody will do such calculations, that is why the optimal dose is usually determined empirically. So, ensure that the pieces of food served are no more than 1/2 of the crab’s body.

Crabs are not fast eaters. Leave their food in the tank for 10-12 hours before removing it.

Optimal Feeding Time

In nature, crabs are nocturnal animals. Their feeding activity increases at night (a few hours after the onset of darkness). Even though some individuals can be active even in the daytime.

For best results, give them food before nightfall. It will replicate the conditions and environment under which they eat naturally.

Food Variations

A wide variety of foods from the list above should be offered on a rotating basis.

DO NOT feed them the same food all the time. This is wrong.

Ideally, you need to have at least 2-3 different types of products to vary. It will give your crabs more vitamins to improve their immune system and prevent molting problems.

Crab Species and Diet Preferences  

Fully aquatic freshwater Crabs Diet Temperament Plant safe
Thai Micro Crab Detritivore /omnivore Peaceful Yes
Pom Pom Crab Omnivore / Algae eater Peaceful  Yes
Matano Crab Omnivore / Carnivore Aggressive / Territorial No
Panther Crab Omnivore / Carnivore Aggressive / Territorial No
Saltwater crabs Diet Temperament Сoral safe
Arrow crab Mostly Carnivore / Omnivore    Semi-aggressive Yes, with caution
Porcelain Anemone crab  Mostly Carnivore / Omnivore    Peaceful Yes
Sally Lightfoot Crab Omnivore Semi-aggressive Yes
Boxer Crab Omnivore/Carnivore Peaceful Yes
Emerald crab Omnivore Slightly aggressive   Yes, with caution
Semi-aquatic crabs and terrestrial crabs Diet Temperament Plant safe
Red claw crab Detritivore /omnivore Aggressive No
Fiddler crab Detritivore /omnivore Slightly aggressive No
Red Apple Crab Mostly herbivore /omnivore Slightly aggressive Yes
Marble crab Mostly carnivore/omnivore Slightly aggressive Yes
Vampire crab Omnivorous  Peaceful Yes
Tangerine-head crab  Omnivorous  Peaceful Yes
Halloween Moon Crabs Mostly herbivore/omnivore Aggressive   No
Rainbow Crab Omnivorous  Aggressive   No

How do Crabs find their food?

Although crabs have compound eyes, which give them panoramic vision, when it comes to feeding, they mostly rely on their antennae and antennules also called “feelers” (read more about crab anatomy here).

Their antennules have special chemoreceptors that allow them to detect chemicals in the water that are released by the food. By using their pincers, they pass food to their mouths which have 3 pairs of maxillipeds (jawfoot) and a mandible (jaw).

Crabs use maxillipeds to rummage, hold and bring food to the mouth during eating. Unlike humans, their jaws open by moving from side to side.

Interesting fact:  Do you know that crabs have teeth inside their stomach? It is called the gastric mill apparatus which functions in mastication (cutting and grinding) as a prelude to further digestion.

In Conclusion

If you decide to keep crabs as pets, it is really important to know what they eat. Because crabs live in many different places, their diets vary depending on their environment.

While the most commercial diets are very convenient and are well balanced, they should be supplemented with other foods as well.

Make sure that they have a good variety in their menu. It will make them happy and healthy.

10 thoughts on “What Do Crabs Eat and How to Feed Them?

  1. This is very helpful for me, and it definitely helps me take care of my moon crab, the only thing I would correct is that I’ve held him a few times for a short time and he was very calm in my hands, I wouldn’t describe his temperament as aggressive.

    1. Hi Vivian,
      I am glad you find my article helpful!
      Well, as for your crab, they all have their own personalities. You got lucky 🙂
      Best regards,

  2. i have a question if i am going to get a thai devil crab how much land will it need and if i choose to stick his diet to only broccoli and neon tetra flakes will that be ok

    1. Hi Xeno,
      Thai Devil Crabs are terrestrial crabs, they need mostly land (up to 90%) in their tank setups.
      As for their diet, I do not think that it will be a great idea to give them only two types of food.
      They need a well-balanced diet to get all the necessary microelements, vitamins, and minerals. Otherwise, they may get sick or have molting problems.
      Best regards,

  3. I loved this article but My crab is a red apple crab and its a little very aggresive so how can I calm her Michael uncle.

    1. Hi Ayana Mili,
      You are referering to Metasesarma aubryi? This species is indeed slightly aggressive.
      Generally, it happens when there is not enough space for every one. However, if you already have a large tank with plenty hiding places, it just show her personality, thus, can be really hard to calm her.
      You can try to isolate her for a few weeks and introduce again.
      Best regards,

  4. hi im planning to get myself a purple matano crab and im thinking of feeding it eggshels for calsium build, sinking fish pellets (algea and shrimp flavors) and as treats frozen bloodworms, frozen red mosquito larvea and small fruit pieces like apple and banana. is this a good diet or do i need to make some modifications to it?

    1. Hi Jelte,
      Crabs are highly adaptable when it comes to food, and what you have described would generally be good for their diet. However, I would suggest adding vegetables to their diet for a well-rounded nutrition.
      Additionally, it is crucial to vary their food and avoid feeding them the same thing for months, as some aquarium enthusiasts tend to do.
      Best regards,

  5. Hello! I am new to crab keeping and am soon going to house a few vampire crabs. Should I be mincing the food for the crabs? Such as fruits and veggies. Should they be blanched? I’ve only kept shrimps before.
    On that note I would also like to ask if vampire crabs can eat live shrimps? Would they enjoy it? I have many shrimps that are breeding so I may have a constant source of protein for them. Should I kill the shrimp first before feeding? Or will the vampire crabs be ok with the shrimps jumping around?

    1. Hi Rachel,

      When it comes to feeding them, it’s essential to provide a balanced diet to keep them healthy. You don’t necessarily need to mince their food, but offering smaller pieces can make it easier for them to handle. Fruits and vegetables are excellent choices. You can blanch them briefly to soften the texture to compare with fresh veggies. Blanched and fresh vegetables do have differences in their nutrient content, and this can affect how your crabs react to them at different times.

      As for live shrimp, vampire crabs are not strong swimmers. I am pretty much sure that they will not hund down shrimp in the water. So, It will be better at least to stun the shrimp before offering it to the crabs. If you take the shrimp out of the water, it won’t jump; their legs are too weak for land, they’ll just lie there.
      Best regards,

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