If you are looking for something unique to add to your paludarium or terrarium setup then the Thai Devil Crab (Cardisoma carnifex) can be an interesting choice for you.
Thai Devil Crabs are relatively large terrestrial crabs and can be recommended even for beginners. You will need a 15-gallon tank for a couple of these crabs, with clear water, moderate humidity, and temperature.
Unfortunately, the ecology of this species is poorly researched and much is still unknown about them. As a result, there is a lot of conflicting and sometimes totally false information on these crabs. Therefore, I decided to do my own research on Thai Devil Crabs.
In this guide, I gathered everything that is currently known about this species including ideal tank setups and how to care for them.
Quick Notes about Thai Devil Crab
| Name | Thai Devil Crab |
| Other Names |
Soapbox crab, Black devil crabs, Purple Thai devil crab, and Brown land crab |
| Scientific Name | Cardisoma carnifex |
| Type | Terrestrial crabs |
| Tank size (minimum) | 15 gallons (~60 liters) |
| Keeping | Easy |
| Breeding | Very Difficult |
| Size of the carapace |
7 – 12 cm (3 – 5 inches) |
| Size across the leg span |
15 – 20 cm (6 – 8 inches) |
| Optimal Temperature | 22 – 26°C (~71°F – 79°F) |
| Aquarium type | Terrarium or paludarium |
| Water type | Saltwater and freshwater bowls |
| Humidity |
60% and higher |
| Diet | Mostly herbivore / omnivore |
| Temperament | Slightly aggressive |
| Life span | up to 8 years |
| Color Form | Maroon to brownish-grey or greyish-blue coloration |
False Taxonomy of Thai Devil Crab or Lies on the Internet
Here is my rant so bear with me a little bit.
I don’t take anything for granted I need to know the details, therefore, I check everything. So, when I started searching for more information about Thai Devil Crabs I got very confused because every single article on the Internet mentioned their scientific name as – Clariosoma Camifax.
However, to my surprise, I could not find anything regarding this species in scientific literature. Why?
Because according to the Integrated Taxonomic Information System (ITIS) and similar systems, such species does not exist!
It would not be a problem if somebody misprinted the name … but not everybody at once! Nowadays, people are so eager to publish as many articles as it is possible that they copy, steal, rewrite information without even verifying it anymore.
Obviously, I could not trust anything they say regarding this topic anymore and I had to start the research from the scratch.
It is not Clariosoma Camifax but Cardisoma carnifex.
Habitat of Thai Devil Crab
Cardisoma carnifex is a species of land crab found from the Red Sea and the east coast of Africa, across the Indo-Pacific to the Tuamotus, including the southern islands of Japan and the northern Great Barrier Reef.
In Palawan, it is reported in the municipalities of Magsaysay, Dumaran, Taytay, El Nido, and Puerto Princesa City. It also occurs in coastal regions of northern Australia and the Cocos (Keeling) Islands.
In nature, Thai Devil Crabs habit the landward fringe of the mangroves borrowing in the mud to hide and are well adapted to terrestrial habitats. It is also found throughout the high intertidal grove.
Description of Thai Devil Crab
Thai Devil Crabs can grow pretty big compared to some of the other crab species available in aquarium stores.
The carapace of an adult crab can grow to about 7 – 12 cm (or 3 – 5 inches) long, with a leg span up to 6 – 8 inches (about 15 – 20 cm) or even more. The total weight can reach 1 pound (or 480 grams)!
Therefore, it will be better to give them extra space in your tank in case they grow a little larger than expected.
Distinguishing characteristics:
- Mostly maroon to brownish-grey or greyish-blue coloration which gradually disappears towards the sides. Young and newly molted crabs have different shades of purple color, which makes them quite similar to Rainbow crabs.
- The ventral side is cream or yellow-colored.
- Dimorphism in claws (in males, one claw is significantly bigger).
- The claws have almost the same coloration as the carapace. The extreme tips of the fingers are cream-colored.
- Heart-shaped body.
Note: The name Cardisoma comes from Cardi = heart and soma = body.
Interesting fact: Crabs in the genus Cardisoma are able to detect small vibrations on the ground within the range of 10–1500 Hz and 70 dB. Visual acuity increases with body size due to an increase in both the number and diameter of ommatidia (optical units that make up the compound eye of a crab).
Lifespan/Longevity of Thai Devil Crab
Currently, there is no data available on the maximum lifespan for Thai Devil Crabs (Cardisoma carnifex) in the wild.
However, in captivity, they can live at least 5 – 8 years, if appropriately cared for.
Behavior of Thai Devil Crab
Cardisoma carnifex is a fully terrestrial species. In the wild, they can be found many kilometers away from the sea.
However, in order to maintain an optimal moisture level, they construct deep burrows. According to the study, their burrows can reach up to 2 m (almost 7 ft.) below the soil surface, terminating in a chamber at the level of the water table. A very approximate volume of sediment extracted per burrow was calculated for the average burrow diameter giving 778 cm3 (0.2 gallons).
They do not like to change their homes and often live there for their lifetime.
Although these crabs appear to be terrestrial, they have modified lungs and require high moisture to breathe. This is the main reason why they dig such deep burrows.
Like most crab species, Thai Devil Crabs are natural loners. These crabs are not social and do not need to be kept in groups. They usually become more aggressive as they age and there is very high chance that will fight fellow members of their own or any other species.
They are not strictly nocturnal animals. These crabs are relatively active during the night and day. Thai Devil Crabs are not timid.
Features:
- Social: No
- Active: Yes
- Peaceful: No
- Burrowers: Yes
Feeding Thai Devil Crab
Stomach content analysis shows that Cardisoma carnifex are primarily herbivorous preferring tender leaves, fruits, berries, flowers, etc. However, it does not exclude the omnivorous nature that allows them to feed on a wide variety of foods, including small prey.
In captivity, for the best growth, Thai Devil Crabs need a good mix of meats and vegetation. Their feeds should contain protein at a level of about 10 – 15% of the diet.
Foods Thai Devil crabs will enjoy (examples with links to check the price on Amazon), for example:
- Vegetables (like broccoli, cabbages, carrots, cucumbers, lettuce, corn, spinach, peas, squash, leafy greens, etc.).
- Fruits (Apple (only sweet), banana, pearl, melon, mango, etc.).
- Leaves.
- Shrimp pellets.
- Shrimp Granules.
- Fish food (TetraMin® flakes, etc.)
- Shrimp food (Hikari’s crustacean food like Hikari Shrimp Cuisine, Algae wafers, Brine shrimp, etc.)
- Frozen blood worms.
- Detritus worms.
- Brine shrimp.
Leaves (for example, Almond leaves, dead beech, oak leaves, etc.) should always be on the menu, as they feed on these and require the detritus from the leaves.
Interesting fact: There have been reports that some land crabs (including Cardisoma carnifexis) are poisonous but this is almost certainly associated with their diet, as these herbivorous crabs sometimes consume poisonous plants. Once they are kept for short periods and their guts are empty, however, they are safe even for human consumption.
Features:
- Diet Type: Mostly herbivore / omnivore
- Food Preference: Leaves and plants
- Feeding Frequency: Daily
Avoid giving your Thai Devil Crabs anything:
- acidic,
- salty,
- spicy,
- fried,
- smoked,
- sweets (like candy),
- flour (including bread).
It is not good for their digestion and health.
You can also read my articles:
How often should We Change the Food?
You can leave their food for 24 hours before removing it. Leaves can be left for weeks in the tank.
Make sure that whatever Thai Devil Crabs do not consume in one day is removed to prevent moles. Keep in mind that these crabs like to store food in their burrows.
How often should We Change the Menu?
Do not give them the same food for weeks. Ideally, you need to change their diet at least every week.
Do Thai Devil Crabs Need Calcium?
Yes, they do not calcium. As with all crustaceans, calcium is a crucial component of a Thai Devil Crabs’ exoskeleton and overall health.
Calcium can be found in kale, broccoli, spinach, cuttlebones, eggshells, figs, wonder shells, oyster shells, seaweed, seeds, insects, etc.
Always keep a small piece of Cuttlefish bone in their enclosure. Supplement their diet and make sure they get enough calcium (for the exoskeleton) by regularly feeding specialized invert foods.
Cuttlefish bones – link to check the price on Amazon.
| I highly recommend reading my article “How to Supplement Shrimp and Snails with Calcium”. |
Are Thai Devil Crabs Plant Safe?
No, these crabs are not plant safe. They are mostly herbivorous. So, they will eat, cut, and uproot everything that is possible in your tank.
Keeping and Housing Thai Devil Crab
Once again, I will have to warn everybody – almost everything you may see in other articles or wikihow is wrong! Following their instruction is a sure recipe for a disaster.
Cardisoma carnifex are not freshwater crabs or aquatic crabs. They are land crabs. You cannot keep them in small tanks. They require a specific setup to thrive.
The good thing though is that these crabs are tropical and hardy and can survive in your learning curve.
Tank Size:
Make sure to keep Thai Devil Crabs in large tank setups because of its growth potential. Hence, a 15 gallon (~60 liters) is the minimum recommended tank size. These crabs need a lot of surface area to roam.
As adults, one male and one female may be kept together in the same enclosure of 40 gallons (180 liters) or more, but two adult males would need far more space to reduce territorial fighting.
Thai Devil Crabs are very good escape artists. It is good to have your tanks covered as much as you can. They are also pretty strong and can move light lids, so keep that in mind.
Land vs Water Ratio:
Thai Devil Crabs are not aquatic; they are terrestrial crabs. Ideally, the land area should take at least 90% of the space in your tank or even more.
· Substrate:
The tank should be filled with a combination of moist sand or mud into which they can burrow.
In order to dig underground and form a cave, the substrate should always be kept moist enough. It means that it should hold its shape when you squeeze it. However, not so wet that it drips or pools water.
To get “sandcastle consistency”, a mixture of cocofiber and sand will be the best option for Thai Devil crab setups.
Tip: There is a simple trick to test the consistency. Take a pencil and stick it all the way down and pull back up. If the tunnel doesn’t collapse, your substrate is good enough.
The substrate may also require maintenance such as spraying with fresh dechlorinated water on a regular basis in order to keep it moist enough since the moisture in it will evaporate over time.
Important: Do not ever use saltwater to maintain moisture as salt does not evaporate and can lead to a harmful salt build-up.
How Deep should be the Substrate in Thai Devil Crab Setup?
In the wild, these crabs are known to burrow very deep (up to 2 m or 7 ft.). Therefore, the deeper the better. I’d start with at least 10 cm (4 inches) deep.
Substrate options (check the price to Amazon):
Water Bowl and Water Type
Thai Devil crabs do not need a lot of water. So, instead of creating a complex tank setup, you can use water bowls.
The only thing that you need to keep in mind – these bowls should be deep enough to completely submerge your crabs.
Thai Devil crabs are mangrove crabs. Even though they can suffice with freshwater, it would be better to provide them with:
- a bowl of freshwater and
- a bowl of saltwater.
Drinking, or spooning up water with the chelae to the mouthparts, has been documented in Cardisoma carnifex.
To prepare saltwater you can use Instant ocean marine salt (check the price on Amazon). This is a great choice. It is pretty cheap and will last very long. You only need about a half cup of Instant ocean marine salt per gallon.
Note: Do not ever use simple aquarium salt or table salt!
Regarding freshwater, ideally, you need to give them something like bottled spring or distilled water.
If you decide to use tap water, let it age for 24 hours before using it. Tap water contains chlorine and it is toxic to them.
You can also use a water conditioner. For example, Seachem Prime (link to check the price on Amazon) will remove also toxic gases, bind to heavy metals, any ammonia, nitrites, or nitrates present for up to 48 hours.
Temperature
The range of optimal temperatures for Thai Devil crabs is anywhere between 71 – 79 °F (22 – 26 °C). They do prefer a warm and humid environment.
If you decide to use a heat pad, it should cover 1/3 (or less) of the tank so that crabs could move from warmer to colder places anytime they want. This allows your crabs to regulate their body temperature to their needs.
Humidity
Thai Devil crabs are pretty resilient to humidity fluctuations.
This is another reason why they are easy to care for. However, for optimal conditions, it is still recommended to keep the humidity around 60% or higher.
Humidity and Thermometer (links to Amazon):
- Zoo Med™Reptile Terrarium Digital Thermometer,
- Zoo Med Labs Digital Thermometer Humidity Gauge,
- AcuRite 00613 Indoor Thermometer & Hygrometer with Humidity Gauge
Lighting
No special requirements. You may not even need one.
Decorations and Hiding Spots
Thai Devil crabs will appreciate all types of leaves, rocks, wood, plants, PVC pipes, and other decorations to enrich the environment in your tank. It is very important to minimize stress to your crabs by giving them a lot of places to hide.
This is also critical for the molting process!
Related article:
Thai Devil Crab and Molting Cycle
The molting process (the molt cycle) is the process by which a crab grows. Because crabs have an exoskeleton, they must molt (shed the old exoskeleton) in order to grow. It also allows them to restore lost limbs.
This process consists of 4 phases:
- pre-molt,
- molt,
- post-molt.
- inter-molt.
For more information, read my article “Crabs and Molting Process”.
Important:
- NEVER disturb your crabs when they are about to molt. Do not panic even if you have not seen your Thai Devil crabs for a few days in a row! Give it time. This is the most stressful moment in its life.
- Keep putting and replacing food in the tank! You never know when they can come up from the molt.
- Keep giving them calcium-rich food.
- Also, do not remove the old exoskeleton from the tank. It contains lots of minerals and your Thai Devil crabs will eat it later.
Rules: How to Care and Handle Thai Devil Crab:
- Thai Devil crabs are not pets you can play with. Do not take them out just because you want to.
- Thai Devil crabs should never be lifted up by their legs or claws! They can lose a limb by autotomy.
- Do not leave uneaten food for too long. It can cause smell and bacteria in their enclosure. Remember, these crabs like to store uneaten food in their burrows.
- Provide as many hiding places as you can.
- The substrate should be based on sand and Eco-earth to give them a homely feeling.
- Make sure the lid of the tank is closed tightly so that they cannot escape it.
Related article:
Thai Devil Crab – Male and Female Differences
Cardisoma carnifex are sexually dimorphic. There are a few indicators that give away the gender of the animal.
- Claws. Dimorphism is confirmed with the major chelae of male crabs reaching larger sizes than those of females.
- Size. Males are a little bit bigger than females.
- Abdomens. Different shapes of the abdomens. Males have a narrow and slimmer plate (triangular) while females have a broad plate on their belly.
Related article:
Breeding Thai Devil Crab
Several spawns per year may occur with spawning season varying with location within the range. Males mate with mature females. Fertilization is internal.
After approximately 2 – 3 weeks the eggs will hatch and must be released into saltwater for the larvae to survive. Although Thai Devil crabs can be found many kilometers inland, they must return to the sea to spawn and release their planktonic larvae.
The female Cardisoma carnifex releases larvae in large quantities 3 days before the full moon and large larval release migrations peaking 2 days after the new moon, just after dark.
Eggs hatch into free-swimming larvae with several zoeal stages and 1 post-larval or megalopa stage.
Each female releases between 350.000 – 450.000 eggs. Typical development time from hatching to the first crab’s stage is from 22 to 25 days.
After a period in the planktonic larvae, they return to the mainland as megalops or first crab stages.
After that, they start living within burrows of adult crabs, in diverticula starting from the main branch of the burrow.
Nothing is known about when they start to dig their own burrows or how they avoid being cannibalized within the adult burrows. According to the same study, young crabs spend at least 3 years in this environment, probably feeding on leaves remaining from the adult meals. Their gill chamber structure is much less adapted for air-breathing than that of the adult.
Thai Devil Crab and Suitable Tankmates
Even though Thai Devil crabs are not extremely aggressive as some other crab species, they are still not peaceful and inoffensive.
They are antagonistic and territorial (especially males). Males are extremely likely to fight when housed together. Therefore, it can be risky to house multiple crabs in the same tank.
Ideally, they should be placed in a tank alone or with other Thai Devil crabs of another sex.
In this case, crabs should be well-fed at all times and there must be a lot of hiding places. Nonetheless, even having lots of hiding places in the tank and keeping them well-fed will not guarantee peaceful coexistence.
In a paludarium setup, it is possible to keep dwarf shrimp, snails, and fish with them. Thai Devil crabs usually do not show any interest in going into the water.
In Conclusion
In recent years, interest in alternative species in aquariums, paludariums, terrariums, etc. has increased considerably.
Unfortunately, little is known of the life history of Cardisoma carnifex. Combine it with wrong and/or totally false information in other articles regarding Thai Devil crabs care and, as a result, it only creates more confusion and misunderstanding.
Thai Devil crabs are mangrove crabs; they are not aquatic. They spend almost all of their time inland. These crabs have a lot of character, personality, and can be a great addition to your home tank. They will certainly keep you occupied.
References:
- QUINN, N. J., B. L. Kons, K. DIBLE, and U. MEISCHNER. 1991. Reproductive behavior of Cardisoma carnifex (Herbst, 1794) (Brachyura: Gecarcinidae) at Lizard Island, Great Barrier Reef. Mem. Queensl. Mus. 31: 399.
- Local Ecological Knowledge and Biology of the Land Crab Cardisoma hirtipes (Decapoda: Gecarcinidae) at West Nggela, Solomon Islands. Pacific Science (1999), vol. 53, no. 1: 37-49
- An Annotated Checklist to the Commonly Harvested Crabs (Crustacea: Decapoda) from Marine and Brackish Water Ecosystems of Palawan, Philippines. Journal of Environment and Aquatic Resources. 5: 61-82 (2020)
- Behavioral Regulation of Hemolymph Osmolarity Through Selective Drinking in Land Crabs, Birgus latro and Gecarcoidea lalandii. Biol Bull 182: 416-423. (June, 1992)
- Kormanik, G. A., and R. R. Harris. 1981. Salt and water balance and antennal gland function in three Pacific species of terrestrial crab (Gecarcoidea lalandii, Cardisoma carnifex, Birgus lalro). I. Urine production and salt exchanges in hydrated crabs. J. Exp. Zool. 218: 97-109.
- Wood, C. M., and R. G. Boutilier. 1985. Osmoregulation, ionic exchange, blood chemistry, and nitrogenous waste excretion in the land crab Cardisoma carnifex: a field and laboratory study. Biol. Bull 169: 267-290.
- Wood, C. M., R. G. Boutilier, and D. J. Randall. 1986. The physiology of dehydration stress in the land crab, Cardisoma carnifex: respiration, ionoregulation, acid-base balance and nitrogenous waste excretion. J.Exp. Bwl 126:271-296.
- Land crabs (Crustacea: Brachyura: Gecarcinidae) of Singapore. 14: e2021001. DOI: 10.26107/NIS-2021-0001
- Tan AYH & Tan TN (2016) Brown land crab Cardisoma carnifex on Pulau Ubin. Singapore Biodiversity Records, 2016: 129.
- Range extension of the land crab Cardisoma carnifex (Herbst, 1796) to further north on the Pakistan coast (Arabian Sea). Zoological Survey Department, Government of Pakistan, Karachi (SP).
- Cameron, J.N., 1981. “Acid-base responses to changes in CO2 in two Pacific crabs: the coconut crab Birgus latro, and a mangrove crab, Cardisoma carnifex.” Journal of experimental Zoology 218:65-73.
- Harris, RR and GA Kormanik, 1981. Salt and water balance and antennal gland function in three Pacific species of terrestrial crab (Gecarcinus lateralis, Cardisoma carnifex, Birgus latro). II. The effects of desiccation. Journal of Experimental Zoology 218: 107-116.
- Kannupandi, T, S. Ajmal Khan, Mercy Thomas, S. Sundaramoorthy and R. NAtarajan , 1980. “Larvae of the Land crab Cardisoma carnifex Herbst (Brachyura: Gecarcinidae) Reared in the Laboratory.” Indian Journal of Marine Sciences 9: 271-277.
- Lee, M.A.B., 1988. “Food preferences and feeding behavior of the land crab Cardisoma carnifex.” Micronesica 21: 274-279.
- Micheli, F., F. Gherardi, and M. Vannini, 1991. “Feeding and Burrowing Ecology of Two East African Mangrove Crabs.” Marine Biology 111:247-254.
- Morris, S. and A.M. Adamczewska, 1996. “Respiratory, acid-base and ion status during voluntary immersion of the air-breathing crab Cardisoma carnifex assessed in situ.” Journal of Experimental Marine Biology and Ecology 206(1-2): 149-164.
Greetings!
I am so thrilled I found this article! I went to e PetCo and saw three of these in a tank completely submerged with no availability to climb out! I have been looking for this type of pet.
If I get a 20+ gallon tank and fill it with the moist sand etc. can they do well with a bowl to submerge in, or do I need to have a “beach” style set up and get a filter etc.?
If you can offer any advice I would love to do this the smart way and give the animals the best possible chance!
Kindest regards,
John
Hi John Peskey,
First of all, I have little to no trust in Petco.
The point is that you need to check that this is the species they claim to be. Yeap, there are way too many mistakes when it comes to crabs.
It is quite possible that this is not Cardisoma carnifex and some kind of semi-aquatic or aquatic crab.
If it is Cardisoma carnifex, you do not need a filter, just replace the water in the bowl.
As for the sand, I would mix it with coconut fiber. This way it will maintain its shape whereas sand will collapse (I am talking about burrows).
Best regards,
Michael
Hi. So like mr. Peskey did with Petco and getting a crab from there I did as well. I have him in a 40 gal breeder lots of sand,hiding spots and water for him to make his home. He’s deep purple with a whiteish underside and claws seem to be about the same size as well. Thing is that he never goes on ” land” for any amount of time. I can see where he has been but mostly I see him breach the surface for air. Is that odd behavior or what? Also in the remaining water side he has a couple red plecos that he shares his main cave with… Any idea what kinda crab it is?
Hi Chris,
Do you have photos? What size is this? Can you describe how it looks?
Thai Devil Crabs are terrestrial but they can be easily confused with Rainbow Crabs (when young and after molts) which are semi-terrestrial species.
Best regards,
Michael
So I today purchased a similar looking crab from petco of course, they didn’t even have a proper label first of all for them, fully submerged in water 4 of them, said they’d been there for two weeks..
Glad I came across this.. I have pics.. Please get back to me..
Hi Antione,
Can you show me the pics?
Best regards,
Michael
Hey there! I really enjoyed reading your post, as there were no other articles regarding this species.
I recently got a Thai Devil Crab as a pet, and was talking about the species in my community, until one person told me that the water for these crabs must have:
(He said that too low ph levels would cause the crab to have molting problems)
the [ph] level of at least 7, and the [kh] value of about 12.
Is this true? Should I adjust my waters so that it has ph: 7, kh: 12?
(My current water’s ph and kh are: PH: 6.4 / KH: 10
Hi Hjfabre,
As I mentioned several times in the article – Thai Devil crabs are not aquatic crabs, they are not even semi-aquatic crabs, they are land crabs! This is their nature.
Thus, there is no need to give them a lot of water. A small bowl with distilled water will be enough for them.
I think that those guys who told you about water parameters confused Cardisoma carnifex with Cardisoma armatum (Rainbow crabs), these species may look very similar. However, Rainbow crabs are semi-aquatic and do need hard water.
Best regards,
Michael
Thanks for the answer.
However, I must say that I do have a land based tank. It’s just that the tank is so huge that the water bowl is also big.
https://youtu.be/wqWy-9z3rqo
You can check out my crab here. As you can see, there’s a lot of land area.
https://youtu.be/Zy8KzjqZ3Yc
And here’s the water tank, which is also huge.
(I know that there’s no need for this big water tank, but still, I have one:D)
The people in my community says that the PH: 6.4 / KH: 10 will harm the crab, when it comes to molting. So I want to know if this is true, so that I can change the water for my crabs.
Well… So maybe even you’re not really sure when it comes to water parameters regarding Cardisoma Carnifex. I hope they could molt in soft water, but I will try to change my water to the water of Cardisoma Armatum for now.
For now, my crab larvae seems to be surviving in my soft water, so maybe it could be the same for the adults? I’m not sure.
Regarding the planktonic larvae and the water parameters for the adults, there seems to be no to little information out there, so I really hope one day, someone could give more information regarding this species.
However, your article was the best I’ve read so far, so thank you once again, and have a great day!
Hi,
I cannot argue with their nature.
It is a fact that adult Cardisoma Carnifex does not need a lot of water (except spawning time).
So, why do we provide them with water at all?
Because we cannot create a perfect environment for them. For example, as land crabs, they make very deep burrows where they can have enough humidity. In addition, even our biggest setups are not big enough for most animals that we keep as pets. In the wild, they can cross large distances with puddles, etc. on their way.
Therefore, we provide them with different types of water to make sure that they have some options that they can easily find in the wild. Even though these options are not mandatory. because of their lifestyle.
Distilled water is enough for adults. If you want to have a complex system with filtration, I’d go for PH 7.0-7.5 and GH 6 – 8.
Larvae and adult crabs have different requirements. Their larva requires only saltwater.
Unfortunately, there is no information regarding their breeding in captivity.
Best regards,
Michael
Hello again!
I wasn’t able to reply to your latest PH comment as I couldn’t see a reply button.
In any case, thanks for the reply.
However, now I have a different question.
You said they require water that is deep enough to fully submerge the crabs.
My tank however, is currently just about this deep.
https://imgur.com/a/oIqpxLE
If they crouch, they can fully submerge. If they don’t crouch however, they seem to be out of the water, even if it’s only partially.
Even though they’re land crabs, I know they molt in water just like Rainbow crabs. But as you said, they’re land crabs, so I’m not so sure if they will drown while molting(Even if I give them aeration, I’m not sure). Will they molt fine if the water is just that deep? Or should I increase the water levels?
Hi hjfabre,
Sorry, didn’t see your question.
It seems deep enough for me.
As for the molt, land crabs have a little bit different approach. For example, aquatic crabs absorb water to create a temporary hydrostatic “exoskeleton” of pressurized water that supports the body while the new shell hardens. Land crabs need only a small amount of water for that because instead of water they mainly use air. During molting, land crabs trap air in their body. This inflates their guts and puts pressure on the hemolymph. As a result, it causes expansion throughout the body and provides the stiffness of their shell.
Best regards,
Michael
Thanks for the answer, once again, Michael!
This time however, I just wanted to say a couple of things.
In Korea, there are a lot of people who had Cardisoma Carnifex, and all of them tell me that their crabs molted in water, even though they’re land crabs.
It is true that they seem to prefer land over water, but they seem to use water when it comes to molting, just like Rainbow crabs. So maybe they’re semi-aquatic crabs who are just called land crabs? Just a thought.
https://imgur.com/a/GJDhr5r
Here are the photos/videos of people who had Cardisoma Carnifex molt in water.
+ For comparison, I posted a photo of my Gecarcoidea Lalandii, which is a true land crab that molted on the ground.
Hi
I also recently picked up a “Thai Devil” Crab just like described in this article and he has no interest in land. The tank (fully sumberged) i first saw him in at the pet store did not have a label on what he was and on the receipt it said Thai Devil, but im not sure that’s what he is. Any help would be greatly appreciated. thanks
Hi Mackenzie Jones,
This is the reason why I do my own research and why I do not trust pet stores.
They often do not even know what they are selling.
I am pretty much sure that this is not Thai devil crab if it prefers water over land. This is against their nature!
They are scientifically classified as terrestrial crabs.
Can you send me some photos of your crabs? Can you take photos of its back and claws in particular?
Best regards,
Michael
I suspect I have a purple Thai devil crab. It was labeled as such at Petco and I tried looking itup and the pictures seem to match. So I set it up as a land set up with a water bowl. She is either a young crab with not so developed gills for land breathing or I have the wrong species because she lives in the water bowl and shows little interest in the land area. I made sure it was damp enough to create caves and burrows with too.
Is there any way I can send you pictures of her so you can ID?
Hi Elena,
Yes, send me the pictures, please. Check your email.
How big is your crab?
Thai devil crabs can be easily confused with Rainbow crabs. Especially when they are young.
Best regards,
Michael
So who wrote it first? Same article, different site …(removed link)…
Hi A,
I can tell you for sure that when I wrote this article everybody mentioned them as Clariosoma Camifax. I did a lot of work and study to find information about this species publish the article.
Unfortunately, lots and lots of my articles are rewritten.
It is very disheartening to see when your work is rewritten by hired writers and published on other sites.
Best regards,
Michael