Thai Devil Crab – Detailed Guide: Care, Diet, and Breeding

Have you heard about the Thai Devil Crab and wondered what it is exactly? If yes, then trust me, you are not alone. When I learned about the Thai Devil Crab, I was intrigued to learn more, so I conducted my research and found out all that there was to learn about these magnificent creatures.

And thus, I complied all my research to create Thai Devil Crab – Detailed Guide: Care, Diet, and Breeding. This guide will brief you about all that you need to know about Thai Devil Crab. Take a look.

All about Thai Devil Crab

Despite their labels, these crabs are nice and quiet. Their maximum growth ranges between 2″ and 3″. These are some vibrant crabs that would look great in your aquarium. You should also make sure they have access to an area with only sand and no water.

They enjoy digging down into the sand and emerging into the water from beneath the sand. Dry fruits, fresh vegetables, and fresh meat are other favorites.

thai devil crab

Thai Devil Crabs are medium-sized terrestrial crabs that are suitable for novices. For a pair of these crabs, you’ll need a 15-gallon tank with clean water, moderate humidity, and temperature.

Unfortunately, the ecology of this species has received little attention, and much remains unknown about it. And thus, there is a lot of contradictory and often utterly erroneous information about crabs.

What Do Thai Devil Crab Look Like?

When compared to some of the other crab species available at aquarium retailers, Thai Devil Crabs may grow very large. An adult crab’s carapace can measure 7–12 cm (about 3–5 inches) in length, with a limb spread of 6–8 inches (about 15–20 cm) or more.

Crab, Crustacean, Sea, Ocean, Water

The total weight can be as much as one pound (480 grams)! As a result, it’s a good idea to allow them a little extra room in your tank if they grow a bit bigger than intended.

Characteristics that set it apart:

The color is mainly maroon to brownish-grey or greyish-blue, and it fades away towards the sides. Young and recently molted crabs have varying shades of purple, making them look a lot like Rainbow crabs.

The ventral side is golden or cream in hue.

In claws, there is a dimorphism (in males, one claw is significantly more prominent).

The claws are nearly identical in color to the carapace. The tips of the fingers have a cream hue to them.

Body in the shape of a heart.

The lifespan of Thai Devil Crab

Crab, Amazon, Colorful, Creepy, Legs

Devil Thai Crabs are hardy crabs that are easy to care for and last for 5 to 15 years. You can take care of your purple Thai devil crabs by providing them with a healthy home and attending to their requirements daily.

The behavior of Thai Devil Crab

Devil Thai crabs are scavengers, which means they scour the area for scraps of food and waste that they may claim as their own. They’re also nocturnal, so this scavenging will take place at night when they’re most active.

Crabs climb everything, and they can climb just about any surface they come across. Everything will be climbed, including airline tubing, intake tubes, boulders, driftwood, and poles.

As a result, you’ll need to ensure sure the fish tank they dwell in has a tight top and that any holes that develop over time are patched.

Additionally, all crabs molt, so if your crab is resting on his back, he might be molting. If he’s acting strangely, keep a tight check on him to ensure that’s the case.

Many freshwater crabs benefit from a little freshwater salt, so pick some up at your local pet store or order some online and follow the directions.

Habitat of Thai Devil Crab

Cardisoma carnifex, also known as the Devil Thai Crab, is a land crab found from the Red Sea to Africa’s east coast, to the Indo-Pacific to the Tuamotus, including Japan’s southern islands and the northern Great Barrier Reef.

Crab, Galapagos, Ecuador, Nature

It may also be found in northern Australia’s coastal areas and the Cocos (Keeling) Islands. Thai Devil Crabs are highly adapted to terrestrial settings and live on the landward border of mangroves, borrowing mud to conceal. It can also be found in the upper intertidal zone.

How to Keep Thai Devil Crab at Home?

Here is the best way to keep your Thai Devil Crab

The Size of the Tank

Because of their capacity for development, Thai Devil Crabs should be kept in extensive tank configurations. As a result, the minimum suggested tank capacity is 15 gallons (60 liters). These crabs require a large amount of surface space to move around.

One adult male and one adult female can be housed together in a 40 gallon (180 liters) or more extensive habitat. Still, two adult males would require significantly more room to avoid territorial warfare. Thai Devil Crabs are excellent escapologists.

It’s a good idea to protect your tanks as much as possible. Keep in aware that they are also rather powerful and may move light lids.

Land vs. Water Ratio

Thai Devil Crabs are terrestrial crabs, not aquatic crabs. The land region should ideally take up at least 90% of the space in your tank, if not more.


The tank should be filled with a mix of damp sand or mud that they may dig into. The substrate must continually be maintained wet enough to dig underground and construct a cave. It implies that when you squeeze it, it should keep its form.

Crab, Animal, Sand, Crustacean, Wildlife

However, it should not be so moist that it drips or pools. A blend of coco fiber and sand is the ideal solution for Thai Devil crab setups to achieve “sandcastle uniformity.”


There’s a quick way to check for consistency. Stick a pencil down and then pull it back up. Your substrate is sufficient if the tunnel does not collapse.


Never use salt water to keep your plants wet since salt does not evaporate and can cause a dangerous salt build-up. These crabs are known to burrow quite deep in the wild (up to 2 m or seven ft.). As a result, the greater the depth, the better.


The ideal temperature for Thai Devil crabs is between 71 and 79 degrees Fahrenheit (22 and 26 degrees Celsius). They want to be in a warm, humid atmosphere.

If you use a heating pad, make sure it only covers 1/3 (or less) of the tank so crabs may travel from warmer to more excellent areas whenever they wish. This enables your crabs to tailor their body temperature to their specific requirements.


Thai Devil crabs are very resistant to changes in humidity. Another reason they’re easy to look after is that they’re little. However, maintaining a humidity level of 60 percent or greater is still suggested for best circumstances.

Hiding Places and Decorations

All varieties of leaves, pebbles, wood, plants, PVC pipes and other decorations will enrich the atmosphere in your tank for Thai Devil crabs.

It’s critical to reduce stress in your crabs by providing plenty of hiding spots. This is especially important throughout the molting process!

The Molting Cycle of the Thai Devil Crab

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The molting process (also known as the molt cycle) is how a crab matures. Crabs must molt (shed their old exoskeleton) to develop since they have an exoskeleton. It also enables them to replace limbs that have been lost.

There are four stages to this process:

  • pre-molt
  • molt
  • post-molt
  • inter-molt

How to Care and Handle Thai Devil Crab?

Crab, Crustacean, Evertebrat, Nature

Purchase an aquarium tank.

Devil Thai crabs can be found in the wild around rivers. Keep your crabs’ aquarium as near to their natural environment as possible to keep them happy and healthy. To house your crabs, you’ll need at least a 5-gallon aquarium tank.

Purchase a tank that will accommodate the quantity of Devil Thais you own. A 5-gallon tank will be enough if you have one to three crabs. If you have numerous Devil Thais, a tank of at least 10 gallons is recommended.

For every 5-6 crabs you have, increase the tank capacity by 5 gallons. This will keep your purple Thais healthy and keep them from overpopulation.

Place the aquarium in a warm location.

Devil Thais dwell in a naturally warm area.

They’ll flourish in water that’s between 72 and 82 degrees Fahrenheit (22.2 and 27.8 degrees Celsius), which you may encourage by placing their tanks in a warm location. Keep the aquarium out of direct sunlight, as purple Thais can be killed by it.

Choose a location

With a constant temperature between 72 and 82 degrees Fahrenheit (21 to 27 Celsius). To help you measure the temperature:

  1. Place a thermometer on the tank.
  2. Avoid exposing the tank to draughty sections of your home or heating gadgets.
  3. Fill the tank with water.

Fill the tank with water.

Purple Thai devil crabs can be found on land as well as in water. As the habitat’s foundation, add a thin layer of sand and some water to the tank. Purple Thais prefer naturally fresh brackish water.

Fill the tank with a small dish of water or pour it in straight. To the bottom of the tank, spread 4-5 cm of the aquarium, play, or bio-sand. If you have a lot of purple Thais or want your crabs to have extra digging room, add more sand.

If you like, you may use coconut fiber as a substrate. Purchase the largest tank you can. No more than one crab per square foot is a fair rule of thumb. Consider purchasing your tank used if you want to save money.

Before using any tanks, make sure they’re clean. Purchase a tank screen to prevent your purple Thais from escaping and climbing out.

Fill the tank with 1.5-2 liters of brackish water. Most pet retailers sell a commercial freshwater salt combination. Mix 1.5-2 liters of dechlorinated water with 1 gram (0.035 oz) or 12 teaspoon marine salts to make brackish water.

It’s critical to use dechlorinated water since chlorine can cause your purple Thais to become stressed and die. Understand that the brown and hazy appearance of the water and sand mixture is typical. In a few hours, the hue and cloudiness will fade.

Make the habitat seem nice.

After you’ve added sand and water, it’s time to make your purple Thais feel at home in their new tank. Crabs that live near water prefer to climb and perch on items. Add decorations like pebbles, sticks, and Java moss to keep your purple Thais happy and healthy.

Choose a selection of fresh or fake plants, wood or stick pieces, and pebbles for your crabs to climb and sit on. Even a modest piece of PVC pipe may add to the habitat’s beauty.

Before putting the pipe in the tank, give it a good rinse. Cover it with Java moss, which purple Thai devil crabs like grazing and catching food through.

Breeding Thai Devil Crab

Vast larval release movements peak two days after the new moon, shortly after dusk, when the female Cardisoma carnifex releases large amounts of larvae three days before the full moon.

Crab, Galapagos, Nature, Island, Animal

The eggs hatch into free-swimming larvae that go through many zoeal stages and one post-larval or megalopa stage. Between 350.000 and 450.000 eggs are released by each female. From hatching to the first crab stage, the average development time is 22 to 25 days.

After that, they begin to live in adult crab burrows, in diverticula that branch out from the main branch of the tunnel.

Their gill chamber anatomy is not as well suited to air-breathing as an adult is.

What Do Thai Devil Crabs Eat?

Crabs are mainly omnivores, and their ideal diet consists of a mix of animal and plant foods. They also consume algae and other similar items on occasion.

Steamed vegetables can also be used, but they must be sliced into small pieces. You should also clean the tank regularly and take care of any food that has been left unattended.

Thai Devil Crab and Suitable Tankmates

Crab, Beach, Animal, Dominican, Republic

Crabs are generally docile creatures, making them perfect complements to aquariums with a variety of species. Though certain crab species get along better with their neighbors than others, most crab species may coexist as long as the following principles are followed:

  • Cichlids, for example, are aggressive and territorial fish that should not be kept alongside crabs.
  • Small fish, frogs, and scavenger fish should not be kept with crabs since they can be hostile.
  • Consider fish that love to live in the upper portion of your aquarium. Fish that like to stay in the top and middle water columns will seldom come into touch with your crabs, reducing the likelihood of aggressiveness and predation.
  • Crustaceans may be abrasive when it comes to defending their territory. If you want to keep numerous crabs together, ensure they have enough tank room and hiding spots to avoid aggressive behavior.


Crabs are hardy, easygoing critters that adapt well to a variety of environments and tankmates. However, the more study and work you do, the more content your crab will be in its new habitat.

Thai Devil crabs are a fantastic critter to buy, whether you’re building a crab aquarium or adding a crustacean to a communal tank. They are curious, lively, friendly, and eye-catching as they go about their daily lives, giving limitless entertainment.


Can Red Devil crabs and vampire crabs live together?

They are generally amicable with one another but not with crabs of a different species. Geosesarma Hagen (Red devil crab) and Geosesarma Dennerle (Vampire crab), for example, will fight more frequently if they are placed together. These crabs excel in sprinting over short distances.

Can Thai Devil Crabs live together?

In a tropical setting, Thai Devil crabs thrive. Thai Devil crabs, despite their moniker, are gregarious animals that can live in couples or groups.

Can you keep crabs in a fish tank?

Some crabs may be kept alongside fish in an aquarium, but many require special circumstances and can only be combined with specific species. Crabs should ideally be housed in a brackish aquarium with a sandy bottom and plenty of hiding spots.

About the author

I'm Gulshan, a passionate pet enthusiast. Dive into my world where I share tips, stories, and snapshots of my animal adventures. Here, pets are more than just animals; they're heartbeats that enrich our lives. Join our journey!