Petkeen is reader-supported. When you buy through links on our site, we may earn an affiliate commision. Learn More

Do Halloween Moon Crabs Make Good Pets? 10 Things to Know Before Getting One

Ashley Bates

Perhaps, somehow a Halloween moon crab caught your eye. What is this interesting crustacean? Their coloring is something of a marvel, attracting onlookers with bright purple pinschers and reddish-orange legs. But when it comes to buying one of these exciting animals for your setup, are they a good fit? Only you can decide.

Of course, they have their particular needs and individual temperaments, but we can cover information and care basics. While Halloween moon crabs are easy to care for, they might not be an appropriate pet for your household—so make sure you consider all factors before you buy.divider-fish

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 small, shy little crabs that have been domesticated by crab lovers over time. Also called the harlequin crab because of their striking color patterns, these crabs are a treat for the eyes—showing off 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 salty to thrive.

You might be happy to know that they are relatively easy to take care of, but you still need to brush up on your crab facts.divider-fishbowl

1. How Halloween Moon Crabs Got their Name

Because of their brilliant colors, these crabs get their name after just about everyone’s favorite holiday—Halloween. It’s no wonder, once you look at their festive color patterns.

They have a jet black carapace, vibrant orange legs, and purple pinchers. They have a small yellow portion around the eyes, too. So, they’re dressed and ready for trick-or-treat 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 very 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 lots of 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

halloween moon crab-pixnio
Credit: Pixnio

These aren’t necessarily the easiest pets to keep. Even though they need time on land, they 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 all is well.

4. Halloween Moon Crabs Like to Hide

These crabs don’t prefer the limelight. Good luck getting them to come to play. These crabs 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 (yes, you). 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 very opportunistic eaters. So, you should be very careful what you feed them.

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

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

6. Halloween Moon Crabs are Terrestrial

halloween moon crab-pixnio3
Credit: Pixnio

Halloween moon crabs are terrestrial, meaning they live on land. But they also require both fresh 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 they could drown if they get caught in the water with no easy way out.

7. Halloween Moon Crabs are Nocturnal

Active mostly at night, the Halloween moon crab spends most of their wake hours when you sleep. So, you might not get to see these gorgeous creatures scurrying around the cage much. Halloween moon crabs spend the daylight hours in their burrows.

If you see them at night, though, it can be a real spectacle. You can watch as they finally emerge from obscurity to scour the tank for goodies. Dusk is feeding time. You’ll see your crab combing the cage in search of a midnight snack.

8. Halloween Moon Crabs Have Sensitive Legs & Pinschers

You should never, ever pick up a moon crab by the legs or pinschers—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 pinscher, you can give them healing foods like:
  • Coconut oil
  • Peanut butter
  • Calcium
  • Eggshells
  • Bee pollen

Look for any signs of infection, too. While most crabs can recover with time, some might not do as well. Keep an eye on a possible infection.

9. Halloween Moon Crabs Fly Solo

halloween moon crab-pixnio4
Credit: Pixnio

It might be a cute idea in your mind to get a pair of Halloween moon crabs. After all, can’t they get 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, too. Some cages come with dividers, so you can essentially keep them in the same space, but they’re unable to interact.

You would 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. 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 if you rent a home. If you plan on moving around, it could lead to rehoming in the future. So, you might want to hash out your long-term plan.

11. Halloween Moon Crabs Molt

Every 18 months, your Halloween moon crab will go through a molting period. Molting is when a crab loses its 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—which 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 from this process. Some owners even crush up the pieces to add to their food dish.divider-food2

Before-Purchase Checklist

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

  • You will need a proper cage. Halloween moon crabs need at least a 10-gallon tank with lots of foliage, hiding spots, and places to burrow.
  • You need to maintain proper water sources. Halloween moon crabs require both fresh 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 who 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.


Are Halloween Moon Crabs Right for You?

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 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 get out to chill with you on the couch—this isn’t the right crab for you. Also, if you can’t handle the environmental upkeep, you better pass this guy by.

Other interesting pets:

Featured image credit: Pixnio

Ashley Bates

Ashley Bates is a freelance dog writer and pet enthusiast who is currently studying the art of animal therapy. A mother to four human children— and 23 furry and feathery kids, too – Ashley volunteers at local shelters, advocates for animal well-being, and rescues every creature she finds. Her mission is to create awareness, education, and entertainment about pets to prevent homelessness. Her specialties are cats and dogs.