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Home > General > Do Halloween Moon Crabs Make Good Pets? 11 Things to Know Before Getting One

Do Halloween Moon Crabs Make Good Pets? 11 Things to Know Before Getting One

halloween moon crab-pixnio4

Somehow, a Halloween moon crab has caught your eye. The coloring of this interesting crustacean is something of a marvel, their bright purple pincers and reddish-orange legs attracting onlookers. But when it comes to buying one of these exciting animals for your setup, would they be a good fit? That’s what you need to decide first.

While Halloween moon crabs are relatively easy to care for, they might not be appropriate pets for your household, so make sure you consider all factors—care needs, temperament, etc.—before you buy.divider-food

A Little About the Halloween Moon Crab

Family: Gecarcinidae
Class: Gecarcinus
Size: 2–2.5 inches
Temperament: Shy, skittish
Environment: Terrestrial
Color: Black, purple, orange, yellow

Halloween moon crabs are shy little crabs that have been domesticated by crab lovers over time. Also called harlequin crabs because of their striking color patterns, these crustaceans are a treat for the eyes with their attention-grabbing exoskeletons.

They naturally inhabit parts of Peru, Mexico, and Costa Rica. You can find them in tropical climates in both fresh- and saltwater areas. They live on land but need a fresh supply of salt to thrive.

You might be happy to know that they are relatively easy to take care of, but there are a few things that you need to know about them.divider-food

The 11 Things to Know Before Getting a Halloween Moon Crab

1. Halloween Moon Crabs Got Their Name From the Holiday

Due to their brilliant colors, these crabs were named after just about everyone’s favorite holiday: Halloween. They have a jet-black carapace, vibrant orange legs, and purple pincers. They have a small yellow portion around the eyes too. So, they’re dressed and ready for trick-or-treating every day of the year!

2. Halloween Moon Crabs Do Well in Captivity

An attractive part of owning a Halloween moon crab is that they do quite well in captivity. These critters are highly adaptable, and they don’t require a large enclosure. A 10-gallon tank will suffice for one crab.

These crabs spend their time climbing around on rocks, logs, branches, and other obstructions with ease. They love having little hiding holes and places to stay out of sight.

3. Halloween Moon Crabs Need a Certain Environment

Even though they need time on land, these crabs spend most of their time by the water. You have to keep a precise humidity level: around 70%. The overall cage temperature should never drop below 78 degrees Fahrenheit, as they are ultra-sensitive to these changes.

These crabs require low light but warm temperatures. So, they do best with low-wattage bulbs to keep warm while maintaining proper humidity. It can be a bit tricky to get things just right, but you can buy thermometers and hydrolyzers to ensure that all is well.

colorful halloween moon crab
Image Credit: Guillermo Guerao Serra, Shutterstock

4. Halloween Moon Crabs Like to Hide

These crabs don’t like the limelight and prefer a hands-off approach. If you see them out and about in their enclosure, they’re probably foraging, not looking for attention.

It would help if you had foliage and hides for your crab to slink into to get away from any scary giants lurking around their cage. They love to feel secure and unseen, and they will probably have a routine and a favorite hiding spot.

5. Halloween Moon Crabs Are Herbivores

Halloween moon crabs are omnivores, but they’re opportunistic eaters. So, you should be careful what you feed them.

A Halloween moon crab’s diet mostly consists of:
  • Raw coconut
  • Leafy lettuce
  • Commercial crab food
  • Seeds
  • Boiled eggs
  • Peanut butter

Like many other crustaceans, Halloween moon crabs need a calcium supplement to make sure their exoskeletons stay healthy and capable.

6. Halloween Moon Crabs Are Terrestrial

Halloween moon crabs are terrestrial, meaning they live on land. But they also require both fresh water and saltwater to live. They live in burrows that they dig themselves in soft terrains like sand.

These crabs cannot swim, so make sure to keep water levels low and land plentiful. There’s a possibility that they could drown if they get caught in the water with no easy way out.

7. Halloween Moon Crabs Are Nocturnal

The Halloween moon crab is usually awake while you’re sleeping. So, you might not get to see these gorgeous creatures scurrying around the cage much. Halloween moon crabs spend daylight hours in their burrows.

If you see them at night, though, it can be a real spectacle. You can watch as they emerge from obscurity to scour the tank for goodies.

close up of halloween moon crab
Image Credit: Jay Ondreicka, Shutterstock

8. Halloween Moon Crabs Have Sensitive Legs & Pincers

You should never, ever pick up a moon crab by the legs or pincers—even if you’re afraid of being pinched. You can seriously damage or even break off one of their extremities.

If they do lose a leg or pincer, you can give them healing foods like:
  • Coconut oil
  • Peanut butter
  • Calcium
  • Eggshells
  • Bee pollen

While most crabs can recover with time, some might not do as well. Keep an eye out for a possible infection.

9. Halloween Moon Crabs Fly Solo

It might be a cute idea in your mind to get a pair of Halloween moon crabs. After all, won’t they be lonely? Luckily, solitude doesn’t bother these crabs whatsoever. They quite prefer it. Owning a pair or more might result in needless fighting and injury.

If you do buy more than one, you might have to opt for separate enclosures. Some cages come with dividers, so you can essentially keep them in the same space, but they’re unable to interact. You will have to make sure both sides have equal access to food, fresh water, and saltwater in this circumstance.

10. Halloween Moon Crabs Have a Decent Lifespan

You can have a moon crab for around the same amount of time as some other domesticated animals. On average, they live around 10 years with proper care. That means before you purchase, you need to be aware of the lengthy commitment to crab care.

Halloween moon crabs might run into a few health issues:
  • Calcium deficiency — Halloween moon crabs need plenty of calcium in their diet to protect their exoskeleton.
  • Humidity issues — If the aquarium has unbalanced humidity, it can cause molting issues and exoskeleton problems.

Remember that you might not be allowed to have this type of setup in your apartment or if you rent a home. If you plan on moving around, it could lead to rehoming your crab in the future. So, you might want to hash out your long-term plan now.

11. Halloween Moon Crabs Molt

Every 18 months, your Halloween moon crab will go through a molting period. Molting is when a crab loses their top layer of skin to start fresh. It would help if you kept their cage very dark at this time. You shouldn’t handle your crab at all but remember to offer meals regularly.

Don’t try to disturb your crab if they are hiding. They need this period to complete the process with no stress, and it can take up to 8 weeks.

Don’t get too freaked out if your crab eats their exoskeleton. It’s totally normal and even encouraged! It has high levels of calcium to help your crab recover. Some owners even crush up the pieces to add to their food dish.

close up of halloween moon crab
Image Credit:, Shutterstock


Before-Purchase Checklist

As with any other pet, Halloween moon crabs are a huge responsibility. They might seem easy because they stay in a cage most of their lives, but they require very specific care to thrive. Before you take the plunge, consider everything that you will need.

  • You will need a proper cage. Halloween moon crabs need at least a 10-gallon tank with plenty of foliage, hiding spots, and places to burrow.
  • You need to maintain proper water sources. Halloween moon crabs require both fresh water and saltwater, so you need a specific setup.
  • You need to respect space and boundaries. Halloween moon crabs aren’t traditional pets. It would be best if you appreciated the fact that these critters don’t care for human contact. To prevent stress and aggression, limit handling time.
  • You should research the species heavily. These crabs are unique creatures that require very particular environments. Make sure you do your homework and set up their terrarium accordingly.
  • You need to provide an adequate diet. These insectivores need a rich diet of all their required nutrients. Keeping a routine feeding schedule is highly advised.
  • You should find an exotic vet in case of emergencies. Like any other pet, your Halloween moon crab needs to have a designated veterinarian with crustacean experience.



If you’re a crustacean lover with prior experience, Halloween moon crabs will make your crib look fab, but they’re definitely not right for everyone. If you think that you can handle the hands-off caretaking method and specific aquarium requirements, they might be the ticket for you.

But if you want a new pal that can chill with you on the couch, this isn’t the right pet for you. Also, if you can’t handle the environmental upkeep, you better pass this crab by.

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Featured Image Credit: Pixnio

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