# 10 Gallon Setup For Fiddler Crabs



## tootie123 (Dec 23, 2007)

I have a 10 gallon aquarium that I want to setup for fiddler crabs. I already have most of the materials needed and Im going to be getting the rest of the materials soon. I have a heater, filter, decorations, water dechlorinator, and loads of fish food. I'll only have to get sea salt, a thermometer, a hydrometer, and a test kit. With the fiddler crabs would I need sand with the fiddler crabs or would I need gravel? I also have some river stones that I bought from Petsmart that go great with the natural looking gravel. The tank has a natural look to it and I thought it would look great with a few fiddler crabs. When mixing the sea salt, should I just put the salt in a bucket with water and mix it together then check the water with the hydrometer. I was also told that when I get the fiddler crabs I will just need to drop them in the water instead of acclimating them. Is that true? I heard tha fiddler crabs dont get to be that large, but Im still trying to decide how many to get.


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## tootie123 (Dec 23, 2007)

Anyone there?


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## tootie123 (Dec 23, 2007)

Can anyone help? Im getting them tomorrow.


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## tootie123 (Dec 23, 2007)

Hello???? Anyone


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## tootie123 (Dec 23, 2007)




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## Guest (Dec 30, 2007)

I'm not sure if anyone on the board has Fiddlers. Give them a little more time, as people are still busy with holiday stuff and not on the website as much. Sorry you haven't gotten a response yet.


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## tootie123 (Dec 23, 2007)

Ok I think I can wait alittle longer.


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## Plecostomus (Jul 31, 2006)

Well, I haven't kept fiddler crabs, but I have kept other types of crabs, and mine did just fine with gravel as a substrate. Also, you probably already know this, but crabs are very good at escaping from tanks, that's actually how I lost mine. Before it left, though, It would always sit on part of the filter so it was halfway in the water and halfway out of the water.


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## tootie123 (Dec 23, 2007)

How big do they get? Im gonna redo my tank to see which setup looks better.
And do they need their own little hideouts? How many can I get?


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## Obsidian (May 20, 2007)

Do a search for fiddler crabs on this website. I think there is one person who has posted about them, but for the life of me I can't remember who it is. If you run that search you may find them and see if it was anyone recent. 

Goodluck!


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## Guest (Dec 31, 2007)

I did some searching for you. 

http://www.fishforums.com/forum/invertebrates/16423-fiddler-crabs.html?highlight=fiddler
http://www.fishforums.com/forum/brackish/16186-feeding-crabs.html?highlight=fiddler
http://www.fishforums.com/forum/invertebrates/11923-2-basic-fiddler-crab-questions.html?highlight=fiddler
http://www.fishforums.com/forum/invertebrates/6553-fiddler-crab-home.html?highlight=fiddler

That should atleast get you started. There were alot of threads that may be older when I searched. Also, alot of people posted in the Invertebrates section, so you might want to browse through the pages of that section.


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## Obsidian (May 20, 2007)

Okay I admit it, I was lazy. Kristin, you are awesome for not being lazy  Happy new year!!!!


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## tootie123 (Dec 23, 2007)

I picked up a new thermometer, a hydrometer, and a bag of marine salt. I mixed some of the salt with the water I had in the tank already. How long should I wait before testing the water with the hydrometer? I ended up getting the one that you fill with water. The directions they gave are a bit complicated so I'll need some help with that. The water is abit cloudy from the salt and I have the filter running in the tank to agitate the water. And someone told me that they dont need a heater and they are fine at room temp. Is that a true statement? In about 3-4 days I'll be getting a couple of fiddlers.


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## fishbone (Jan 15, 2007)

Tootie, sorry, I haven't been on board for a while. I have experience with keeping these guys, including red claw crabs. I have a 10g with a red claw female and a 75 gallon palludarium with 7 fiddlers. If you wanna see pics, let me know.
On to your questions.

The set-up you have drawn looks good. In my experience, fiddlers don't spend as much time on land as one would think. "Fiddlers" can be a LOT of the Uca subspecies to their behavior might vary. Most fiddlers you get from LFS spend about 80% of their time in water. My land area is 24x9 inches and although there are "foot" prints all over, I have yet to see my fiddlers on it. They only come on at night. I say this because the most important thing is the WATER area, not the land area. So, if you had to choose, go at least 60% water and the rest land, because the more water, the more steady the parameters. It is hard to build a good palludarium [half land, half water] in a 10 gallon, I would recommend a 20 long.
Also, I would not get more than 2 fiddlers at the most for 10 gallons. Depending on their size, you could try your luck with 3. NO MORE than 1 male. So get 1 male, 1 female, or 1 male and 2 females. I had 10 fiddler crabs in my 75 gallon: 3 males, 7 females. I STILL had territoriality and aggression issues. The population kinda evened itself out and I am left with 7, which are much happier now.

A concern I have is the depth of that sand. It may develop anaerobic pockets which harbor toxic bacteria. No good. If I were you, I would probably build the incline with rocks or gravel, or just give the fiddler crabs access above water using tall rocks or decoration. I considered ways to do this for my 10 gallon and I have yet to come up with a good way to do it. I considered building some sort of floating or fixed device covered with sand, never came up with anything good. We have a lot of creativity here, I encourage input on this matter 

Water questions.
First off, try to keep track of the volume of water you have, it will make things MUCH easier in the future.
What you need is brackish water with a salinity between 1.004 and 1.008. Unfortunately, hydrometers are inaccurate in this range. If you have the money, invest in a refractometer. They go for about 20-30 on eBay. I can recommend a good seller. But if you're careful with your mixtures a hydrometer will do just fine. To get the salinity you need, mix 2 leveled tablespoons of marine salt for each gallon of water. The salt I recommend is Instant Ocean, it dissolves very fast. Mix the salt in with your hand or something else, use your dechlorinator [I recommend Seachem PRIME because it is so much more than just a dechlorinator], let sit for about 10 minutes and check and see if anything has deposited to the bottom. If you see salt on the bottom, mix some more. In my experience, Instant Ocean is exactly that ... instant. I only have to mix with my hand for about 30 seconds, let sit for 5 minutes and it is good to go.
DO NOT vary your salinity. The crabs can take the swings, but your bacterial colony ... not so much. If you swing salinity you might see a mini-cycle and that's NOT good. So try to keep the salinity pretty steady. STAY ON TOP of your water level. Make sure that you compensate the water when it evaporates, with FRESH water, because salt doesn't evaporate. If you compensate with brackishwater, your salinity will rise. What I do is I mark the normal water level on the side of the aquarium and try to keep it at that.

Temperature
If your ambient room temperature doesn't go under 74*F, you are fine. Crabs like it between 74-ish and 84 IIRC.

Cycling
DO NOT get the crabs if your tank is not cycled. Invertebrates, including crabs, are VERY sensitive to ammonia. They will NOT survive the cycling process. Search the forum for information on how to cycle your aquarium if you need to.

Fiddlers are messy eaters. You will have to do partial water changes once a week, especially with a tank like yours. 30% should be good, you can go more. I feed mine once every other day.

BTW, what I have capitalized, I am not yelling. It is just my way of underlining important information 
I am now subscribed to this topic, so if you have questions, I'll be around.


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## tootie123 (Dec 23, 2007)

I purchased my fiddlers yesturday. I only purchased 3 just to be on the safe side. I think they are all females. I'll have to check again. They hardly do anything. They just sit around in the corner between the filter and heater. They occasionally go up on land. I haven't fed them yet. Im kind of not sure how to place their food. Will they eat shrimp pellets?


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## fishbone (Jan 15, 2007)

If both their claws are the same size, they are females. Males have a HUGE left or right claw.
I feed them Hikari Tropical Crab Cuisine. This is what I'm talking about. I also feed them raw shrimp, peas, carrots, raw fish. Just keep in mind that they are tiny. Don't overfeed or you will get ammonia spikes. Happened to me. Feed them no more than half of a half of a pea per crab. I feed them every other day.
The Hikari stuff works great for several reasons: it is the PERFECT size, doesn't pollute the water, doesn't break down and it is specially formulated for crayfish/crabs. I feed mine once every other day and I alternate between veggies and meat.
Shrimp pellets are just fine.

Did you cycle the tank? What are your readings? Did you slowly acclimate your crabs when you introduced them? Lethargic crabs is usually a bad sign. Could mean osmotic shock, ammonia/nitrite poisoning, sick crabs, etc.
Make sure they also have hiding places. You could go to Wal-Mart and buy the smallest tiniest ceramic pots you can find, bury them halfway on their side in the substrate and this will make great natural looking caves for them. They will NOT be comfortable without hiding places and will be stressed out.
I'd expect yours to moult any time now. Usually happens because they get moved from totally-inadequate-LFS-freshwater to brackish. This has triggered moults in all the crabs I've ever gotten. Some have moulted as soon as the very next day


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