Anyone familiar with fiddler crabs?

[HaydenHermie]

I've really gotten into crabs ever since the hermit crabs. I started thinking about different pets that I've had in my lifetime, and all of the crabs. I'm a Cancer (zodiac sign), so I've always been facinated with the crabs, the crab symbol, and everything involved with that. (Finally figured out why I just love crabs so much!)

Anyways, I remember having crabs once upon a time. I have no idea what happened to them. They were small, walked sideways, and staid in water and on land. I'm assuming they were fiddler crabs. Now, I don't know if my old setup that I had was correct or not. We had water with a rock inside of it that broke onto the surface so that the crabs could climb up out of the water. I don't remember food that I fed them, or anything like that. Finding information on them kind of sucks. Some sites say they need brackish water, some say they need fresh water, some say that they need marine grade salt water. Some say that they can eat fish food, some say that they eat normal, regular food... I'm completely confused.

Unfortunately I haven't found a Fiddler crab fan site (hehe), that could tell me how to properly keep these kritters. I love watching the crabs and how they walk and how they work together. But I remember my old encloser smelling really bad (probably due to poor caring. I was really young). So I'm not entirely sure if that's just part of the crabs or part of the tank that I had once set up.

Anyways, just wanted to know some information on the crabs. I have NOTHING set up for them yet. Simply just gotten curious about other species of crabs (aside marine hermit crabs, not a huge fan of the marine hermit crabs). Any information is appreciated! =)

[parrothead]

I don't have any input, I have LHC and MHC, no Fiddlers yet... however, they're several people here that have them and I am sure they will chime right in good luck

[HaydenHermie]

Thanks. =) I'm assuming their care would be similar to how MHC are maintained, just with a surface area above the water. But you can never be too sure. I find it more helpful finding information from people who actually own then, than from commercial places. XD Obviously, the advice from petstores has been proven wrong many, many times. Haha.

[parrothead]

yeah, I believe they require brackish water

[Happy Crabber]

http://www.hermitcrabassociation.com/ph ... dler+crabs

Did you see this thread? This is Wode's experience with Fiddlers. A very interesting read- I'm sure she'll fill you in later.

[HaydenHermie]

Oh wow! I didn't notice it was about fiddlers!! Really excited. *stalks post* Haha.

I'll definitely been snooping around the post to find information. Thanks a lot!

[wodesorel]

If you have any questions, let me know! I still have one of the first females I bought, and the giant male from last year. Unfortunately they are known for sudden death at around the three month mark in captivity, even if they have molted successfully. If they're transported and kept in brackish water this doesn't seem to be much a problem, but very few stores do this. I have lost a few of the new girls I got in the last few months. ( If you had smelled the water they came in it wouldn't have been much of a surprise. A few were even fuzzy with mold or bacteria. I'm quite happy that a few have made it!) If they make it to four months there's a good chance they'll live for years.

I would recommend against keeping more than two males in the space of a 20 long, and only one in anything less. The girls are fine together at seemingly any number, and he'll like his harem and keep them safe. However, males don't seem to enjoy other males in their space, and I unfortunately learned the hard way that when the other boys grow too big they will be killed. (When they've been crushed straight through, there's no doubt on cause of death.)

Trying to keep a sloped beach tank with sand will lead to a foul smelling tank filled with dangerous bacteria unless it's stirred around once or twice a week. My original set-up was like that and it was awful! The new tank is wonderful and smells like salt water and fresh soil. So glad I changed it out for something that was more a fish tank with a land platform.

As far as food they don't seem to be too picky. I do fish food most nights, also frozen and dried shrimp. They love the sardines that I give the hermits. I also have dried seaweed (lavar) that I bought at an Asian Grocer, and I feed that two or three times a month as it takes days for them to work through it all. (I wish I could tell you exactly what it is, but I can't read the package!) They also like dried crickets, and I put this on the land section for them. They really like guppies. Fruit never gets touched, but veggies like zucchini will. They have about a 50/50 died of meat to plant matter, so both should always be available.

And yep, real fids (one really large long claw, one teeny small) will always be brackish. Between 1.005 and 1.010 is ideal for them. I keep mine at 1.010 since I also have the marine hermit crabs. (Which may not be working, I haven't seen them in a while.) There are other species of crabs that are called fiddlers by the stores, but these are not related and can come from fresh, brackish or salt depending on the species. Those types of crabs will have two even claws, or just a slight difference in size between the two.

They will bury and dig in substrate if you can provide it to them. Mine have burrows in the land section that are really hard to spot, but if you watch you can see them dash in and dash out throughout the day. I'm using peat moss with a little sand as that seems to mimic debris-filled estuary muck pretty well. I know that people have kept them successfully with them just having a way out of the water.

[HaydenHermie]

Your previous thread has been such a huge help! I'm thinking about using your tank setup to kind of give me a model for a tank setup of my own. I'm thinking of taking a plastic tub of a size, using that as the land sand area, and then filling around it with water, with a climb up of probably left over needle point canvas and aquarium-sealed sea shells/gravel.

The pet store that I see them at only carry maybe one or two at a time. I have NO idea what size tank requirements they need for one or two of them. They don't even have specifications on the tags at the store.

Idealy, I'd like to keep the water and sand separate. I think that's why my older tank had smelled so bad. Do they thrive in larger communities? I've heard that males are more solitude than females are.

So I can pretty much feed them what I feed Land Hermit Crabs? That's good to know. Makes dinners easier. XD

If I use gravel instead of sand on the marine side... is that bad? I don't really like the idea of cleaning sand in an aquarium. Gravel just cleans out a little easier. XD

Sorry if I bombard you with questions. I'm just so intrigued that there's really little to no information on these crabs for captivity. =/

[wodesorel]

Sand versus gravel... I don't like sand either, but for how much they like it, it's worth it. it gives them perfect traction, is nearly identical to what they would have in nature (silty sandy estuary, not rocky stream or coral beach), and they can also bury down in it or dig under things. I only used about a half-inch, and the playsand is very easy to clean compared to the fancy white sand I used in my 20G aquarium. (THAT stuff is like flour!) I run my fingers through it about once a month and gravel vac what I can. The trick is to rinse the sand extremely well before you add it to the tank to remove any dust and any of the lighter bits that would float around and cloud the water.

I do think they are like hermits in that they do best in numbers, so ideally it would be one male to a group of females in a tank less than 29 gallons. In a 30 gallon (since it's longer) I believe that two males would do fine as long as there is heavy cover at either end for them to lay claim to and they were about the same size. The females seem to prefer being crowded and I often find them all piled together. The males will be wherever the girls are doing their "Hey Ladies" dance, so they aren't exactly solitary. They just don't mix well with other males.

If you only wanted a few then a 10 gallon would be fine for one male and maybe two or three females. They don't swim like fish, so they really only need a few inches of water depth, although more water will be better for keeping it clean. Even when fully grown they aren't a huge animal. A 20 long would be better since it would give them more space to run.

Trying to figure out a filter for them is the tough part. A regular fish filter normally won't work since the water level will be too low. You'd need to use either an internal filter that was modded so it hung low enough, or a canister filter, or a even a turtle filter. Have you had fish before? Know what cycling is? The tank will need to be filtered and cycled to keep their gills from burning, unless you can do water changes once a day.


And yeah, there is basically NO care info on these guys! A lot of it is guessing. I went back to basics and figured out what species I had and where it came from, and went from there as to temperature, salinity, diet, etc. It seems to be working as I still have the same crabs after more than a year, and the females are regularly producing eggs.

I started here:
http://fiddlercrab.info/index.html

And I also used this blog for guidance as well, and she had really detailed notes about how she kept her crabs. She even managed to hatch out babies, but I don't think any survived:
http://soulmosaic.wordpress.com/2008/01/

There were days in the beginning that I wanted to e-mail the guy who ran the fiddler crab site (he's a prof at a university) and beg for help since he studied them so much! They really aren't too hard though - water like any aquarium, mimic nature as best as possible in terms of set-up and temp, and treat them like shell-less hermits.

[HaydenHermie]

Oh yes, I cycle all of my tanks that have at least 50% water in them. =) I plan to do so with the crab setup, as well.

The filtration was another problem that I was running into. I was thinking of getting one of those micro filters, one seen previously in someones' crabitat pools. Seemed easier to get those. The smallest filter I have ATM is a 10 gallon filter. I'll definitely have to pick up smaller filters *adds to fiddler need list*. And I can use playsand? Just rinse it off thoroughly? That's awesome. Sounds practical enough for me. I was thinking you had to do the whole pantyhoes cleaning system every week. Did it once with a fish tank. Never again. But I can siphon, that's no biggie at all. I could also cut up a bit of a sponge filter and make it like a smaller, shorter sponge filter? I'm trying to think how I could make that happen with a low water line... I'm sure there's a way.

Do they surface molt? I haven't heard much of them needing to barrow a whole lot. I know that they enjoy it, and that's fine, but any requirements like the 2-3 times deeper than their bodies kind of thing?

Hmm... now that I'm seeing that they'll appreciate a 20 gallon more, maybe I shouldn't get them? I don't really have the space for a 20 long, quite honestly. The only open surface area I have would fit a 10 gallon, max. MAYBE 15 gallon if the demensions aren't as larger. But I think other than that, I'm max out of room since I just set up the 10 gallon ISO tank for the crabs and the 5 gallon bait tank. Even the 10 looks small for a crabitat that needs running room. =/ Hmm...

[wodesorel]

I really think they would be fine in the 10. Try to give them lots of areas to climb and hide and they'll be happy. Floating plants are huge - they love to stick themselves in the filter output with just their eyes out of the water and wait for dinner to float past.

I've never heard of the pantyhose thing before? I've been using sand in my 20G for five years now, and I just gravel vac. I've got thousands of teeny tiny MTS in there to stir up the sand so I don't have to. The fids do a great job of sand stirring if it's thin enough. The hard part is that first rinsing. Rinse, stir, rinse, stir, rinse, stir for like 20 minutes straight depending on the bag you buy. I found that going with 5 pounds at a time in a deep bucket works the best, and just keep rinsing until the water is crystal clear. Outside would be best for this!

The water should still be cycled 10 times an hour, ideally, so make sure to check the GPH on any filter you're looking at. If you only have 5 gallons in there then you'd only need a 50 GPH filter. (Which some of those micro filters are. ) Again - sorry if you know this! I'm never sure how into fish anyone is.

They will molt in the water, and it's a fast process - just *zip* and they're out! They harden to normal color in just a few hours, and they will normally eat their exo so just leave it where it is. I've never had them cannibalize each other, and they seem to be okay with sharing exo.

And totally know what you mean about room! I've got to get another 10 or 20 in somewhere for the original dad hisser and junior so they don't make any more babies. (I think mom was in labor this morning, so I just moved dad in with another species that he couldn't breed with temporarily.) I'm thinking it will have to be in the bedroom. >< And then I have to find a place to set up another 10 gallon in preparation of hermit crab babies. I have no idea where as I'd like it to be someplace where it won't have to be moved at all for the next month and where I can actually work on it without killing myself. And there is absolutely no room to move in the invert room as it is! I got ahead of myself. I knew the room was coming soon, but I moved too fast and now I'm tripping over tanks left and right.