HCA: Hermit Crab Association

Member AP reported success keeping fiddler crabs with hermit crabs. They say there's no agression, and the fiddlers just need 2-3" water pools, and they also enjoy the mix of salt water and fresh water. In the wild, fiddlers and hermits are often found in the same area.

[Link no longer works]

I can't view the page since I am not a member there. Sounds like an interesting story, could you maybe post it here?

AP:

I have Fiddler crabs in with my hermits. Does anyone else have any other species in their crabatat? Mine all get along fine but if my hermits are enjoying their dinner and don't want to share they will flick (Like a finger flick) the hermits away the poor fiddler he goes flying but neither will hurt the other. I find that the fiddlers are the clean up crew (mold, hermit poop, hermit mites and and bug larva. They do everything that the hermits do but no shells, and they will escape if your not careful as they like to climb. I need deeper water dishes about 2" to 3" but a added moss and sponge stops anyone from getting stuck in a water bowl, they like both salt and fresh water. I also use gravel under their feeding station easiest to clean its in a plastic bowl buried in the sand up to the edge. I have 3 different substrates play sand mixed with calci, coconut and gravel. I use plastic dividers to keep them separated I have all sizes of Hermits in my tank From small 1" to jumbo (Tennis ball) and now 3 fiddlers. I just got a new little girl.

http://landhermitcrabs.com/eve/forums/a ... C00149.JPG

JediMasterThrash wrote:In the wild, fiddlers and hermits are often found in the same area.

Yep. Saw it myself, too. Well, actually, they weren't fiddlers, but those red-clawed Sesarma (sp.?) "mini-" crabs similarly occuring in the ecological niche occupied by fiddlers elsewhere - it was a mangrove swamp in the Philippines (Puerto Azul) with C. rugosus and copious amounts of mudskippers! =) =) =)

That is a very cool observation. It is neat how two species of animals can coexist in a tiny tank.

MudCrabDude, you must have had quite an experience. I think I remember seeing photos or you talking about your trip. Seeing Coenobita rugosus must have been thrilling. Especially when you think, "These little guys sold in pet stores all lived here once."

Kilimanjaro wrote:That is a very cool observation. It is neat how two species of animals can coexist in a tiny tank.

MudCrabDude, you must have had quite an experience. I think I remember seeing photos or you talking about your trip. Seeing Coenobita rugosus must have been thrilling. Especially when you think, "These little guys sold in pet stores all lived here once."

Yes, indeed! Actually, the trip I mentioned above was in 2003; the ones I posted with photos were in 2006-2007, hehehe. Unfortunately, the latter trip did not accrue any wild rugosus crabs in pics, only the few sand crabs and that one coconut crab in a Singapore zoo (which Annopia/Caroline also met =) ).

That little quote you mentioned is EXACTLY what I had in mind when I first witnessed it on my trip on 2003. I've been watching such shows on PBS and on Discovery and so on on television, but witnessing firsthand was such a...well...sort of an epiphany, so to say. It was so ...

...awesome.


By the way, wild rugs are prone to biting when picked up, hehehehehe. Also very hairy, too!

But it was even neat seeing them almost everywhere: the lower tree trunks, near the parking lot, climbing the guard rail of the bridge that crossed the little mangrove swamp...

The fun thing was also when it rained later afternoon: these guys began popping out everywhere! Tiny walnut-sized shells began crossing our path back to the car... LOL

You know, I have thought that it would be neat to add some fiddlers or "mini" crabs to one of my tats but, I was always afraid that the little buggers would get hurt by the hermies. I will have to give it a try. I love fiddlers. They are a blast to watch when they are showing off to their girls . Not that I would put one of these in with a hermie but, I used to have a couple of "halloween crabs" They were super neat.

It would be neat indeed. Of course setting up a large enough vivarium is a challenge in itself, though not impossible (quite pricey, too, unless one shops around for bargains).

Here is something I came across once that might help you set one up:

http://badmanstropicalfish.com/brackish/brackish.html


Scroll down to "mangrove swamp"

I might set one up just for a couple of straws in the future (which keep dying on my "conventional" setups...)

Also, I had previously experimented with a 50/50 tank (half-dry, half-marine saltwater) with land hermit crabs. During a molt, a land hermit crab will try to dig and hide only in relatively dry areas; they will never dig into the water line, unlike fiddler crabs which will tend to make subterranean pools when molting.

I've always wondered how a land hermit crab grows without immersing itself in salt water like it's marine cousins...that is where the molt sac comes in, I think.

Anyway, I've also found that land hermit crabs are much messy diggers that they disrupt the natural sloping of the beach, also causing the uphill substrate to be saturated with water that it becomes unable to bury and hide, and thus molt and cause health problems (unless it's a solo crab in a large tank and it does a surface molt, which almost always in my case happens because the whole setup becomes so saturated with mud and water).

So pretty much a few of the problems I encountered is:

1. How to maintain a dry and wet area in a relatively small enclosure when the crabs dig.

2. Filtration and mud; how to filter the H2o without mucking up the impeller of the filter itself, as these waters will be inherently silty and muddy.

I've also tried creating some plastic dividers in the tank itself, none of which have yet worked with me at least.

Sorry for the long rambling...

I'm not quite sure I understand how this person set their tank up to accomodate both the hermit crabs and the fiddler crabs

Hi
AP's Tank is 25 gal divided in to 3 area's.each is separated by 6" flexible plastic, ( The tank isn't separated just the substrates are) 1 coconut fiber 6" deep, 1 play sand mixed with calcium sand 6" deep, and aquarium gravel that is used as feeding station that has 2 water bowls which are salt and fresh the water they are in glass containers 6" round 5" deep with under gravel filters (She made these out of an old 10 gal filter she wanted the tube hole for the bubbler) a bubbler, or the air stones are split from one pump this puts air in the water and keeps the waters fresher longer and helps with humidity. The fresh water container have living moss and other things to climb in and out on. Salt has broken shells and more things to climb out on that way hermits will not get stuck and drown, She has lots of air plants and logs to climb and grows veggies in tiny pots for them too. She has Mirrors on the outside end of the tank. There is no Mud in her tank the fiddlers eat what the hermits do, dig and molt in the sand like the hermits and are in and out of the water as the please and all live very well together, they climb on the things the hermits do and hide under the things the hermits do,
AP has a kind heart. and She tends them like she would tend her garden. She is 63 yrs old and has had hermits since the 1960's. She is My Mother. She won't get back on the computer because someone hurt her feelings. I have watched her take a Hermit who has lost limbs in a fight she gave it baths in Aloe and hand feed it till it molted and it lived. She chirps to them and yes they chirp back! She had 6 hermits and 3 Fiddler crabs. What exactly they are I don't know.

MudCrabDude:
Also, I had previously experimented with a 50/50 tank (half-dry, half-marine saltwater) with land hermit crabs. During a molt, a land hermit crab will try to dig and hide only in relatively dry areas; they will never dig into the water line, unlike fiddler crabs which will tend to make subterranean pools when molting.

This is a very interesting observation. In my most successful crabitat itrations, I did not keep the substrate moist. Water dumping out of the bowls would help, but usually whenever a crab needed to dig, they'd moisten it themselves by dumping shell water and then dig a hole.

But in some of my less successful crabitat iterations, I tried to keep the substrate moist (under the assumption it would be better for burying). I would pour one or two cups of water into the substrate once a week (keep in mind it's a large tank).

And then I stopped, and the substrate is mostly dry on the top again, but the crabs don't seem to be having any problems.

So I think you might be on to something, that maybe we shouldn't artificially moisten our substrates.

On the other hand, it seems my little guys/teens much prefer to bury in already wet sand. The'll always bury in the super-moist areas right around the waterdish. But I'm not sure if they actaully do their molting there.

Don't fiddler crabs need brackish water? Or would they be okay having access to both fresh and salt water?

Fiddler Crabs
The Fiddler Crab is a small crab ranging in size from about one to two inches. They are found in sandy or muddy beaches and mangroves of West Africa, the Western Atlantic, Eastern Pacific, and the Indo-Pacific. Fiddler Crabs are also known as “Calling Crabs.â€

JediMasterThrash wrote:This is a very interesting observation. In my most successful crabitat itrations, I did not keep the substrate moist. Water dumping out of the bowls would help, but usually whenever a crab needed to dig, they'd moisten it themselves by dumping shell water and then dig a hole.

But in some of my less successful crabitat iterations, I tried to keep the substrate moist (under the assumption it would be better for burying). I would pour one or two cups of water into the substrate once a week (keep in mind it's a large tank).

And then I stopped, and the substrate is mostly dry on the top again, but the crabs don't seem to be having any problems.

So I think you might be on to something, that maybe we shouldn't artificially moisten our substrates.

On the other hand, it seems my little guys/teens much prefer to bury in already wet sand. The'll always bury in the super-moist areas right around the waterdish. But I'm not sure if they actaully do their molting there.

No, wait...LOL.

When I meant about wet areas, I was talking about really,really saturated with water where fiddlers and mini crabs (and some Florida land crabs apparently) need to dig into to create "subterranean pools" in order to have proper brackish/salt water in order to expand their shells after shedding in order to grow, like their marine counterparts without being out in the open.

I still think the moisture is needed to create the "sand castle consistency" to create their subterranean subchambers, the land hermit crabs do, but they never dig into and below the water line.

The land hermit crabs I had at least stopped digging 1 inch above the water line, and when the artificial beach eroded, which the digging tends to do, my land hermit ended up molting above the sand and sometimes on the rocks because my tank got too saturated On the other hand, the fiddler I had would leave cast off molted shells just like 1 inch under the water.

Oh yeah, and as a side note, I've witnessed fiddler crabs cannibalize each other in captivity...yiiikes!!!!! (this is the brown and white fiddler sold in freshwater aquariums around California - I presume it comes from the brackish areas of the Amazon...???).

And, the moisture might add some extra benefits as well, such as facilitating breathing during their long fasts/aestivation prior and after the molt.

Well, I still am not sure apparently. I'm still a supporter of keeping substrate moist for land hermit crabs, but not too saturated with water, opposite the case for the fiddlers (who seem to require an area saturated with brackish water in addition to a dry area as well - something that seems to be neglected for fiddlers in the petshop - which are often kept purely under[fresh]water - or the halloween land crabs - which I've seen kept bone dry (!!!)

I will have to do some experimenting. I have a 55g getting ready to open up that I think I will play around with. My hermies seem much happier with the sand castle consistency sand. That is how I keep all of my tats.