Halloween Crab Information

The Halloween Crab (Gecarcinus quadratusor) sometimes known as the Purple Moon Crab is a gorgeous, terrestrial crab that can be a unique companion for hobbyists. This crab has vibrant purple claws, beautiful orange legs and a carapace that varies in color but is usually dark with a pattern that looks like a face. Like many crustaceans, they are often kept to be observed and not handled. Keepers of this terrestrial crustacean often focus on having the enclosure as a centerpiece and only having the crab as a resident. You won’t always see this nocturnal crab. Many times, it’ll be hiding in its burrow throughout the day and it is more likely to explore its domain at night.

When fully grown, this terrestrial invertebrate will grow to be around 5 to 6 inches in length when fully grown. Its carapace will be roughly 2 – 2.5 inches once it reaches adulthood. It also has a pretty long lifespan. Under ideal conditions, your Halloween Crab can live between 8 and 10 years. This guide will go over enclosure requirements, food & dietary needs, compatible tank mates and breeding potential.

Enclosure Requirements

This species of crab is fairly easy to care for, but still have a few requirements that need to be filled. A single Purple Moon Crab should not be kept in anything smaller than 15 gallons. They are incredibly territorial and may fight with other crabs, especially other male Purple Moon Crabs. If you plan to keep more, make sure the enclosure is large enough to accommodate more crabs. This species of crab does better solitarily compared to Vampire Crabs which do well in small communities. Follow this link to get information on Vampire Crab care.

Lighting, Temperature, & Humidity

Because this species of crab is nocturnal, it only requires a heat lamp to keep the enclosure warm and to provide UVA for the crab. Keep in mind that heat lamps are a fantastic way to warm this crab’s home. The optimal temperature to keep this crab happy is between 75° and 88° Fahrenheit (~24° – 29° Celsius). The Halloween Crab will also require humidity levels to be 80% or higher. An automatic mister or manual misting will most likely be needed daily.

Substrate

The Halloween Moon Crab loves to dig. In the wild, they can dig a burrow several feet underground. That is not very practical in an glass box. It is important to provide at least 6 inches of substrate so this crab can create a burrow. Providing plenty of burrowing space is important because the Halloween Crab can disappear into their burrow for days and maybe even weeks. They will also hide in it when stressed as well as when they are molting. Sand/soil substrate is an excellent choice for this species of crab. I would not recommend digging them up because it can cause a lot of stress.

Watering

Halloween Moon Crabs love getting the best of both worlds. This is why providing them with both freshwater and saltwater pools to dip themselves into is important. The pools only need to be deep enough to moisten the gills of the crab. Although the Purple Moon Crab is an excellent climber, the pools should be easy to enter and exit.

Safety

As stated previously, the Halloween Moon Crab is an excellent climber. It is important to have a lid not only to help increase humidity levels but to also keep your crabs from escaping. These little escape artists can sometimes climb up the silicone of an aquarium or wires to sneak out of its enclosure!

Food & Diet

Halloween Moon Crabs are omnivorous scavengers in the wild. They will usually eat anything they can get their claws on. However, their diet primarily consists of more fibrous material such as leaf litter, detritus, algae and fruit. Your feeding regime should reflect what they eat in the wild. Your Halloween Moon Crab will eat the following:

This list is not exclusive. They will eat many other types of food offered. This list is to provide you with a good variety of foods that can be offered to your crab. Protein rich foods such as crickets and bloodworms should only be given to your crab as a treat. Lastly, food should not be kept in the crab’s enclosure for more than 24 hours.

Many foods can provide calcium for a Halloween Crab. However, I feel it is almost a requirement to keep cuttlefish bones in the enclosure to provide an extra source of calcium.

Tank Mates

I personally would not keep anything with a Purple Moon Crab. These invertebrates are very territorial and can injure other wildlife with their claws. Their claws can also cause another animal to die from injuries. With a large enough enclosure, one male may be able to live in the same environment with a female or two. However, there will always be a chance of fighting between the two which can lead to serious injury or death.

If the water portion of the enclosure is deep enough, fish, snails, and shrimp can be housed with a Purple Moon Crab. This is possible if you are fine with any of these animals disappearing and potentially becoming a snack for your crab because they are opportunists.

This species of crab loves to “redecorate” its home. If you keep plants in with one, you may have to plant and re-plant ones that have gotten ripped out of the ground.

Breeding

Breeding Halloween Moon Crabs is incredibly difficult. Large enough enclosures, aggression levels and the fact that females go into saltwater to release their eggs makes it incredibly difficult to successfully breed this species of crabs. It’s an interesting challenge but I have never bred this animal, so I have zero insight on the topic.

Final Notes

Halloween Moon Crabs are a gorgeously colored animal that are slowly gaining fame in this hobby. They have unique personalities, and are very fun to observe. If you’re interested in keeping a more hands-off animal, I would recommend this one as a pet if you love crustaceans and owning something incredibly different, while also taking on the challenge of its environmental needs.

Image by Dexxfire on wikiMedia