Fiddler Crab Tank?

[Perfectblue]

I think a tank specially designed for fiddler Crabs would be different as well as interesting. I've been trying to find as much information as I can but have not found very much. I would like to set up a small tank for a group a Fiddler Crabs. Here is my plan:

10 or 20 gallon long-half water half land
Sand or fine gravel substrate
Whisper 10 internal or Zoo Med canister filter
Rocks, caves, wood, and fake plants

Brackish water(SG 1.005-1.010)
Temp: 75-82F-will try and find small enough heater or else I will use a heat lamp
Feeding: bottom feeder pellets, shrimp pellets, as well as freeze dried foods every so often.

I have some questions first.

1.) Does the water portion need to be cycled? or can I add the crabs right away?

2.) I would like to set up the tank as half land half water where there would be a total water volume of 3-6 gallons. Would this be enough water?

Any help you can offer me would be great.

[Boxermom]

1. yes to cycle
2. yes

[Pyratt]

Probably you already knew this, but my experience with them:

Fiddler crabs are escape artists, but usually won't go tooo far from home (I found mine chilling on top of the filter, inside the filter itself, behind/under the filter...). My guy never actually left his tank tho.

I ran a mostly-full-water tank that had a tall piece of driftwood that stuck through the water for an inch or so and he'd perch on that more often than on the filter.

I suppose tho as you're running a low-water tank you'll be using an internal filter, you just need to make sure your lid is secure where the cord runs up.

-pete

[kass]

It'll prbably be hard to get the whisper filter to work, with the water level low. I would go for the canister, or an internal filter. I have a fluval 2+ on my mudskipper/ fiddler crab tank and am pretty happy with it.

[dc519]

i was gonna put some fiddler crabs in my GSP tank but the lady thought I was just gonna use them as food. truth is, i was gonna see if my GSP could/would eat those little guys. but i wouldnt mind them in the tank either. only problem is that there would be no place for them to be out of water...unless as Pyratt stated, out of the tank somehow.

[TheSmJ]

I understand that if the fiddlers have adequate land space to walk around and possibly build a burrogh they'll stay in the tank without incident.

You can kill a fiddler if they're not given land space to walk around on. Its a biological requirement for these guys.

[kass]

I agree land space is improtant, my fiddler spends almost half the time on land, or in the very shallow parts.

[nmonks]

As an aside, and an alternative to fiddlers, there are numerous brackish water hermits crabs... the problem is recognising them! Apparently the small blue legged hermit sold as a marine invert does well in brackish water. Not done this myself, but been told by many reliable aquarists. Also seen this species (or close relatives) in estuaries along the Florida coast, where the tidal sections are literally crawling with hermit crabs.

Anyway, the species is Clibanarius tricolor, known in the trade as the dwarf blue-legged hermit crab and it is from the Atlantic coast of North America. Grows to around 2 cm (plus shell) and needs an SG of at least 1.010. Primarily a scavenger, but should be offered some food of its own, such as small pieces of lancefish or mussel. Aggressive among their own kind, particularly if the snail shells they use as homes are in short supply. But harmless towards fishes.

If adapting a hermit from a marine aquarium store to your brackish water tank -- TAKE YOUR TIME! Inverts tend to be a bit more delicate than fish. So while you can dump an adult scat from a marine tank into a 50% seawater brackish tank, doing that to a hermit will kill it. Adapt it over several hours. I'd take all day, to be honest.

Cheers,

Neale

[The Fisherman]

Good to know neale, I may try that myself. I'd want to positively ID my hermits though. Mine are sold as blue legs, but who knows if they are the type you mention. I have seen some as big as an inch or 2, plus the shell. They have the blue and yellow legs. (I think theres a picture of one doing a handstand in my gallery, if you want to check it out)

[nmonks]

Hmm... your hermit crab is very cute indeed, but I'm not sure it's C. tricolor. There's a nice picture of this crab outside of its shell on this web page at the Natural History Museum of LA County.

My assumption has always been that many of the generic crabs and hermits sold to marine aquarists are simply tidal and shallow water animals captured easily and cheaply. Assuming that's the case, probably quite a few of them are euryhaline animals, just like many shallow water marine creatures in the temperate zone.

Cheers,

Neale

[The Fisherman]

Thanks neale, after looking at the picture, I think your right, that it is not C. tricolor.

I'm going to start a new topic on brakish water hermit crabs, to try and not hijack this thread

[nmonks]

I'm sure there are other brackish species, too. A little time spent on Google might be useful. You might also check out biological supply companies within the US; there are quite a few, and they collect various things for universities, marine labs, and so on. Not necessarily cheap, but at least they can get you a specific species. Otherwise, maybe time to plan a trip to FLA?

Cheers, Neale