Halloween/Moon crabs care???

[claymore]

I bought a pair last week end at a herp show.

I've reesearched them all this week and have a good understanding on care and what not.

The only conflicting info I read was on salt water... Some sources say use it and some say Don't!

So which is it???

Has anybody else on here kept these marvelous little crustacians???


Thanks

Clay

 

[naturejoe]

crabs

I have kept them a few times and each time they would do great for months and then would die. I did not offer any saltwater. I think it is best to emulate nature as much as possible and these crabs dig burrows below the water line to create little pools of saltwater. There must be some reason. Good luck.

 

[LeilaNami]

I believe it is the same with hermit crabs. They will drink the fresh water but offer salt water in a bowl as well because it is very important for long term health. I believe it is used more frequently when the crab is ready to molt.

 

[Andrew273]

Been a while since I kept hermit crabs and never had any other kinds. I think they put the saltwater on their gills to breath. I could be wrong but I definitely recommend giving them a bowl of it.

 

[RoachGirlRen]

I would provide a pool of freshwater and a pool of brackish/saltwater. Make sure that you use MARINE SALT however, not table salt, as iodine and caking agents can harm the crab and the mineral content of marine salt is different from most food salts.

ETA: I just did some reading on these guys because you've made me curious, and while several studies have indicated that chloride and sodium are not limiting factors for the species, it is suspected that some ion in marine water is, as they do not tend to distribute too far inland from coastal regions(1). So chances are if they are suspected to need it in the wild, it should be offered in captivity. It also had some notes on diet in the wild which includes a significant amount of leaf litter and seedlings, so I'm thinking it may be beneficial to include leaf litter and sprouts in their diet as opposed to just processed crab diets.

1. Dry season distribution of land crabs, Gecarcinus quadratus (Crustacea: Gecarcinidae), in Corcovado National Park, Costa Rica - Griffiths/Mohammad/Vega

 

[spydrhunter1]

There's a good article on crab street journal on mixing sea water for hermit crabs, it may work for these guys; http://crabstreetjournal.com/xoops/modules/news/article.php?storyid=20

 

[claymore]

Thanks Ren! Is this the same Ren from FatFrogs?

I just finished their tank today! I'll have to run out tommorrow and grab a dish for the salt water. Anyidea how big/deep it should be? do they have to submerge themsel;ves in the salt water?
Anyways here are some pics!

 

[LeilaNami]

You want the dish to be large enough to get their body in and deep enough for them to get a substantial amount on their bodies.

 

[dtknow]

I've observed these in the wild. They were abundant on the beach under drift and around some mangroves in Gauanacaste, Costa Rica. Previous studies have shown they cannot survive if only given access to seawater. Their ionic balance is a little lower than pure seawater and they cannot osmoregulate well enough in that required direction.

I would provide them some fresh water, but also have some brackish/sea water for them to drink to maintain their salt balance. They can also drink out of moist substrate so perhaps freshwater container is not strictly required

To the person who posted tank photos. I think you need more substrate(I would do a mix of fine sand an coconut fiber moistened so they can burrow), and a smaller water section. These crabs do not submerge themselves in the wild(their burrows do not touch the water table, unlike mangrove crab Cardisoma, which also appears in the trade...care for this sp. will be different). Even when releasing eggs into the sea they try to stay as dry as possible, going out to far could mean being eaten by fish.

Mainly herbivores/detritivores in the wild but opportunistic.

RGR: your advice is spot on. I do wonder if the inability for them to go inland is due merely to the need to go back to the sea to breed, or perhaps a habitat preference issue.

 

[Galapoheros]

I think these def need the ocean waters to breed. I have collected these on S. Padre Island, at least they look extremely identical, and the ocean is a big place so I assume they are the same species. The behavior is prob like the xmas Island crab vid I saw. They might not need salt water to exist in their solitary life though. But I would always have salt water available to them, they are def associated with it.

"the ocean is a big place so I assume they are the same species." haha, that wasn't very good logic but there is not much doubt in my mind that the same species can be found in s texas. I will look for some pics I've got somewhere. I didn't bring any back home but it makes sense to keep them like RGR mentioned, offering both fresh and saltwater.

 

[dtknow]

Galapoheros:
Not sure where the OP's crabs are from. But if they are from the Carribean and are Gecarcinus lateralis than thats the sp. that occurs in some spots on the Gulf. They only visit the ocean to breed, and even then try to stay out of it lest they get swept in.

No one has bred these in captivity yet. They'd probably need exposure to the lunar cycles to sync up for breeding. The zoea could be raised on rotifers followed by artemia nauplii(contrary to popular belief crab larvae CAN be raised in captivity, and based on the papers I've read it does not sound too difficult).

 

[Galapoheros]

I could have put this in another thread but we can compare here. They do look a little diff. I saw some that were almost all purple there too, I have a pic of one of those somewhere too.

 

[dtknow]

My bet is the "all purple" ones are Cardisoma guanhumi.

 

[LeilaNami]

The zoea could be raised on rotifers followed by artemia nauplii(contrary to popular belief crab larvae CAN be raised in captivity, and based on the papers I've read it does not sound too difficult).

The what-a-what? My crab speak is definitely lacking. I'll have to look this stuff up lol

 

[Matt K]

I have to agree with dtknow. Thier captive rearing is not difficult but does require some attention, much like propogating jellyfish really, which I have done with several species

While in Costa Rica, I have regularly seen crabs wander inland and found them near fresh water supplies, but this indicated to me that they alternate with some regularity thier intake of salt and fresh water. So (at a guess) if it were I, there would be access to both in the enclosure or make thier water source a little less than brackish.

 

[AudreyElizabeth]

I bought one of these a few years ago and kept it in a tank much like the one pictured. The crab 'appeared' to be doing well until it molted, and it lost four legs! My LPS often has these crabs, but I hesitate to buy another after that bad experience. (The crab died not long after the bad molt.)
However, I did not know at the time that they needed brackish water. Could this have caused the bad molt?

 

[RoachGirlRen]

If there are important trace minerals in the brackish/salt water, it could have been a cause of a bad molt; unfortunately the exact function of salt/brackish to their survival is not firmly understood. Thus it is favorable to provide both fw and sw/bw "just in case."

However, more often than not, a bad molt is from a humidity problem (be it air humidity or a hydration issue) or if the exo itself is bad, a diet problem. As mentioned this species consumes a lot of leaf litter in the wild; I would wonder if insufficient chitin because problematic for them if fed say, your typical hermit crab food.

 

[dtknow]

Also, in the wild they'd probably be at the bottom of a very deep and cozy burrow.

 

[RoachGirlRen]

That too; I know hermit crabs do OK with several inches of damp substrate, but I don't know how much that cuts it for a species that burrows more deeply.

dtknow, do you know if they are opportunistic or obligate burrowers? Ie. do they tend to take over burrows of other species or do they dig their own? I'm thinking of eventually trying my hand at these guys and I'm just thinking of housing options.

 

[claymore]

First off thanks for all the replys!!
I started this thread and walked away for a few days and blamo it has a life of its own!

Ren - They seem to dig they're own burrows and revisit them each day. I'm guessing they would use the same burrow in the wild over and over again, unless they were forced to relocate for food or water or cave in. This species likes to burrow deep! At least mine like to. I have 4.5 to 5 inches of sand on the land portion and they are burrowed all the way down to the bottom!

I am going to relocate them into a twenty long this week end.

I'm taking the advise dtknow and providing more land space and thicker substrate for deep burrowing.

I have a bowl of salt water in there now and I've seen them dipping their claws into it and bringing it up to their mouths. So I think it is a good idea to provide both fresh and salt water!

Like Ren stated above, their diet consists of leaf litter and scavenging. I've been trying a number of diff food items, like... Lettice, slices of apples, pecies of carrots, dried fruit, fresh bannanas, and for protein... a few fresh killed crickets, freeze dried brine srimp, and even a little of my cats wet food (fish flavored). So far they don't seem to be picky eaters. They are messy eaters though!LOL

But I can't find any info on a feeding scheduale! I don't want to feed to often and I don't want to starve them ethier.

Any ideas???