Introduction: Fiddler Crab Care

Picture of Fiddler Crab Care

Since there are about 12 million fiddler crabs dieing every day because of uneducated owners,
i decided to make this instructable
Most of the problem is about how pet store employees are miseducating buyers and telling them the exact opposite of supplies...

Step 1: Supplies

Picture of Supplies

Here are the basic needs for a fiddler crab
-A 5 gallon tank (the bigger the better)
-a heater (Yes fiddlers get cold)
-A filter (Go for the internal ones for fiddlers because fiddlers are great climbers and can crawl up the intake tube and escape)Never go for undergravel filters for crabs...
-Sand (Fiddler crab legs are designed to crawl on sand,don't go for gravel because it makes it hard for them to crawl on and believe it or not fiddler crabs will die of frustration)
-Sea Salt (Fiddler crabs live in brackish water-half salt half fresh-and will die in months if in freshwater)

Note:Fiddler crabs are NOT semi-aquatic,remember they live in beaches not the ocean

Step 2: Determining the Gender

Picture of Determining the Gender

The gender of a fiddler crab is easy to determine,male fiddler crabs have on normal claw and one big claw,while females only have two normal claws

see picture below

Step 3: Choosing a Crab

Picture of Choosing a Crab

Choose healthy, active fiddler crabs with all their limbs still intact. A good set-up is one male to about three females. Crabs are sold in many pet stores. People also like to catch fiddler crabs on beaches.

Step 4: Feeding

Picture of Feeding

Feed your fiddlers algae disks or commercial crab food. They also find shrimp pellets and frozen bloodworms quite tasty. A slice of zucchini is an occasional treat. Remove uneaten food after 24 hours, or you'll be growing mold and smells.

Step 5: Heating

Picture of Heating

Keep crabs comfortable in a room-temperature (75-85 degrees F) environment. If the water is too cold, invest in an aquarium heater or basking bulb.


Picture of MOLTING

When fiddler crabs molt they will eat very little and will stay upside down for many hours, DO NOT touch or mess with your fiddler crab when its molting! Fiddler crabs may look hard but are acutally VERY FRAGILE!
I once accidentally KILLED one of my females when I tried to help it back up...
After your fiddler crab is done molting you may see him eating the old shell THATS OK,fiddler crabs will eat the old shell for nutrition,DONT TAKE OUT THE SHELL EVEN IF THERE ARE NO CRABS AROUND IT! Your crab needs the nutrition and will only it the shell when no ones around (exception for other crabs)
Be sure to isolate your fiddler crab when hes done molting,after he starts to be active and his new shell comes in you can put him back in the main tank...


JaquettaB (author)2017-05-07

My son got 3 fiddler crabs from school two of them died but Hermy is holding on. I am now reading up on fiddler crabs. I would like to move Hermy to a bigger tank and buy two more but I am concerned about what type of sand to buy and where to buy 2 more fiddler crabs. Can anyone HELP me!!!????

DorrettaH (author)2017-02-18

I bought Stress Coat for my aquarium on advice from person working in the fish area. I have 3 fiddler crabs and started looking up different things about them and found out that they need sand and water so they can get out of the water too. So now we are going to transfer the crabs 2 females and 1 male to another container. It says on the bottle to add 2 tsp to 10 gallons. I then read that you should NOT put Stress Coat in the water of crabs here is copy and paste of what they said : Q: Since the Stress Coat is so good for crabs, wouldn't it be even better for them if I let them drink it?

A: NO! Stress Coat is ONLY recommended for bathing the EXOSKELETON of land hermit crabs. It is NOT recommended as drinking water! Do not leave ANY Stress Coat-laced water ANYWHERE INSIDE the crab tank.

It says you can bathe them with and I have never read that the actual crabs need to be bathed. DO they need bathed and if so how often? Anyway, I have already added it to the tank with the fish we had but I am now making their correct habitat as you have outlined do you know anything about Stress Coat and should I NOT add it to the new habitat I'm making for the crabs?

LyndaH24 (author)2017-01-31

Sorry forgot to add that it has sand for burying, algae tabs to eat, place to crawl out of water, and room temp water (about 70) , and only one tank buddy who WOULD miss the crab if he ever even saw it in the first place to miss it, a beta that is so tame, it does tricks !

LyndaH24 (author)2017-01-31

I haz to learnzd me to spellz wenz I bawt a krab sous I kewd axs ewe a kewston. My bad. Sorry, couldn't resist, no harm meant and not directed at anyone. I know....shame, shame on me...but it was a little funny (insert smiley face). So I got this little fiddler crab about 6 months ago and I keep forgetting I even have one since I NEVER see it. That is until I clean the filter. And low and behold....there he is seemingly happily clinging on to the filter. The first time or two I found him there, I put him back into the tank. Once he found a shell and went in it and never came out until I had to clean the whole tank. So when I put him back he just ended up clinging on to the filter again. At first, I was half freaked out that he kept doing that since I would forget I even had a crab, and was sort of worried he was getting accidently sucked up the filter. But then, after about tenth time I realized he was going there on purpose. I guess to eat off of the filter? Anyway, so that is where my fiddler crab hangs out at all the time. I guess its ok to let him hang out on the filter (?) since I have had him (or her) 6 months now and it has grown a LOT from when I first got him. Right? I tank you for your time and comments....get it...tank you? I crack myself up !

hartjose (author)2016-11-27

i need comments about my crab living.

* i have a 3 gallon tank

* i have 3 male fiddler crabs

* i have 3 female fiddler crabs

* i have fish pebbles

* they have access to land and water

* i have treated fresh tap water

Any tips or suggestions?

Candycane382 (author)hartjose2016-12-19

I'd get rid of the fish pebbles get sand, and have fresh water and something with salt water for them because they are salt water creatures. A 3 gallon tank is a bit small for 6 but the pebbles will break their legs. Good luck

AquaFish (author)hartjose2016-12-19

Six crabs in a three gallon tank? That sounds extremely crowded and unhealthy... Treated tap water is good, but I'd suggest adding some aquariums salt, their shells could weaken in freshwater. Finally, by fish pebbles I'm guessing you mean aquarium gravel, like the post above says, if they can't burrow, they could die of frustration, also, their legs could get caught in the gravel and break off. Yes, crabs can grow their legs back, but I'd imagine it hurts and would you like to have something constantly ripping your hair out even though it will grow back?

Candycane382 (author)2016-12-19

I have had fiddler crabs for some time now and a lot of the info you have is great. I also have moon crabs and hermit crabs and before I became a mini pet shop due to my sons I had them all in one tank and they got along just fine. I have them all in different tanks now, they all have different attitudes. My fiddlers like to climb and swing craziest bleep I've seen and I've seen crazy things.

The Emily (author)2016-02-20

I would like to know if I could keep them on gravel... Because mine are living in it right know

Tcollins30 (author)The Emily 2016-08-10

Easy fix, Just add sand into the gravel, maybe remove some but a half half mixture is perfectly fine and will alow them to burry a little.

JudyW60 (author)The Emily 2016-06-18

No they like to dig into the sand gravel stresses them they can die sand sold in bags cheap at petstore.

gunbarrel32 (author)2016-03-07

Most of this is untrue I have two female fiddlers for a month now. They are in a fish tank with many fish totally immersed in water and doing great !!!

JosephE42 (author)gunbarrel322016-05-21

That's one month, wait for more.

WindiH (author)2016-01-19

I would like to know if I should feed and change my fiddler crabs water when they hibernate

Kiana12 (author)2015-11-18

I just bought a fiddler crab, but I wasn't told I needed a heater or salt water. Can I just use tap water for a certain amount of time til I get salt water?

mlaiuppa. (author)Kiana122016-01-04

NO. First you'll have to make sure the tap water has been treated to remove any chloramines your city adds to the water. These will not evaporate just leaving buckets out overnight. If you don't treat tap water whatever you have will die.

I don't have crabs but I have goldfish. The same general rules apply to all.

Their health is dependent on the quality of their environment. I have never had any fish die of a disease because I make sure my water quality is very high and my fish has plenty of room.

If you want your crab to be healthy, make sure his environment is the best you can make it from the very start. If you already bought the crab, that means you need to go back and get whatever you need to supply him with his optimal environment now, not when you get around to it.

DebbieH41 (author)2015-11-07

sorry it's DebbieH41 again my 4 grand children are very happy has I helped them to asked some for help about there pet grab. And what to feed it

DebbieH41 (author)2015-11-07

hi I am look for some information about fiddlers crabs, it's just that my 2 Grand-daughters when the out with there poppa today to a truck show for cancer for kids and on there way bk they stopped at the beach and collected some shells. When they got home they put there shells on the floor and the found the tiniest crab. So could some one please tell me how we can keep it for a pet. I have been reading that u can use fresh water from the tap then some are saying you can't, because I have no idea my 6 yr old grand son has already gave it a name Molly, I hope it's a girl for his sake. Could some one Please help us. Thank you then we can have happy Grand kids, after what they have been thro in the last 24 hrs

Drew145 (author)2015-09-06

Stupid ive had my fidler crab for a year and i have her in a tank full of water she loves it and they eat algae tablets not freekin betta food that floats un reachable

Dorgotravieso (author)2015-08-19


theweeonefromtexas (author)2015-05-21

I recently bought a better fish and a half gallon tank. Immediately after putting him in, I felt guilty and put him in a drink dispenser (approximately 3 gallon) until I could research more. He is now in a 10 gallon take with a place. I kept him in a large net to let him get used to the new guy and make sure he wasn't flaring. Later that night I took him out of the net and let him out into the new tank. He has gotten along great with the pleco so far. My husband and I were talking about getting a freshwater crab to go in. I originally thought a fiddler crab since Walmart keeps them in the same aquarium as a pleco. Just like everyone else, I was misled. But what can you do. So now I'm glad the last Walmart was out and I didn't bring any home. Are there any other crabs that would thrive in a freshwater tank with a betta and a place?

weish (author)theweeonefromtexas2015-06-24

most crabs are actually brackish water, and won't enjoy living in fresh water. crayfish, sold as mini lobsters in some places, are a better choice and quite entertaining.

ryan.leary.7524 (author)2015-04-27

I just bought mine at Walmart yesterday out of impulse. I saw that they were in a tank of water and thought that's how I take care of them not knowing the proper way. This was very helpful thank you

kimberly.roelkemoe (author)2015-04-09

just wanted to say Thank you. I picked up a few fiddlers for my classroom. Your information has been very helpful

RyleeM (author)2015-03-11

I have just bought 2 fiddler crabs from Walmart (Both female) and I had asked one of the workers what you need. I bought rocks and a 1.5 gallon aquarium kit. I had no clue you need a heater and stuff. She only told me to get betta pellets for food and some rocks. She completely did not know what she was talking about and I am very frustrated. Would you think they could survive in 1.5 gallon aquarium kit?

Subotai (author)RyleeM2015-03-31

they were working at Walmart, what did you expect? They get paid minimum wage in a soul destroying job that robs them of their dignity.

SJP Woodcuts (author)2015-03-14

i just bought two fiddler crabs from walmart and now they are sick, won't move and one lost one leg. i think its because i used gravel. thanks for this instructable really helped. will now make a lot of changes!

foodislove (author)2015-01-19

I bought a couple at walmart, and i think these crabs are sooo adorable. Walmart doesn't even know how to take care of them. I make a little beach with some brackish water for them. They are great climbers, and they can grip on anything including glues that are used to make the fish tank and will climb out if there is an opened gap. I feed my crabs with betta pellets, plankton, and shrimp pellets.

Yard Sale Dale (author)2015-01-07

I've had some crabs for a few months in a 5gal aquarium with goldfish and snails. The water is low saline content, and I give the crabs "salad shrimp" occasionally, as well as white "tums" for calcium. They love the tablets and the male crab will sometimes sit on one to hoard it till he's done eating. The snail likes it, too.
The crabs have a plastic castle to climb on to get out of the water. I'm looking at your page to think of a new tank (bigger box) so the crabs get more sand area. Thanks.

NissaP (author)2014-12-31

Hello, need a little help. I am one of those people that did not get good info from the pet store. We got a red crab yesterday and he has already lost 2 legs in a fight with a catfish. I put him in a temporary home and he seems to be doing ok. Should I put time and $$ into a suitable home or will he not survive? Thank you

taylor.greer.58 (author)2014-12-30

As an employee at Walmart, don't blame all of us for poor care.
My Walmart actual takes good care of the fish, got my Gustavo and my baby fiddlers yesterday, all healthy and high active. I have just two fiddlers so I got a single gallon tank until they get larger. I was going to get fine gravel today, but I may get sand instead, but the man told me that I should get an ornament for them to climb on and so they can bask and not to keep them underwater all the time. He actually takes the fiddlers out 2-3 times a day. He like to bring food for them too, maybe some freeze dried bloodworms like my betta loves. but im excited for my babies

pjclaybaker. (author)2014-12-28

my son received a fiddler crab and a red clawed crab for Christmas. We have them in a 5 gal tank, set up as you have recommended. We do not have a heater but do have a basking lamp on most of the day. The crabs do not seem to be eating anything. We put crab pellets in a plastic upside down lid, tried a few little pieces of cucumber and part of an algae tablet. All of it just sits there until we take it out. It's now been 4 days. They seem inactive and spend most of the time hiding. What do you recommend?

backyardswagger (author)2014-12-24

I think my fiddler crab is dead hes been like that for a day plz help

lilsoph (author)2014-12-17

If our crab could talk he would most definitely thank you! We bought it from walmart and set it up as they had him in store.

A week later it was upside down. we presumed dead. Laid there all day until my hubby got him out to get rid of him and noticed he seemed to be moving slightly. We researched (as we should have done right away) and came across your instructions, which we followed. 3 months later he is healthy and active and we are about to get him a couple of friends. So thanks :)

plamay (author)2014-02-16

Thanks for this info. I have been looking and looking and came across your post. We live in Pensacola FL caught some fiddlers actually about a dozen so I actually should return some to the shore. They just seemed so funny and thought the more the merrier LOL. Anyway i pray I can keep the little fellas alive. I brought home some of the water from the shore I was wondering if I can just keep changing out the water from the same shore instead of commercial salts ?

rjoos (author)2013-07-03

This isn't a bad way to do it but if you want fish in the same tank they wouldn't have much room.

I really recommend Underwater Islands they have these really cool products that make it so you can have crabs in your tank but not have to have your tank only half filled.

I attached a picture from their website so everyone can check them out if you want.

their website is

Check it out and let me know what you think!

reine432 (author)2013-06-25

In your instructions you mention "there's a basket under here to hold up the sand, and the heaters under there".
please advise what type of basket you use.
Also another question, when fiddlers molt, ("they will stay upside down for hours") are they ever upside down underwater for hours? I assumed mine was dead- maybe he was molting? thanks so much for all the info!

Climber03 (author)2013-04-19

You can have a way smaller tank about about a quarter gallon

Biggsy (author)2012-09-16

I found this Ible VERY useful when i began thinking about owning some red clawed crab... I have a Facebook page thats sort of part blog on my journey into owning crab, if you have crab, or are looking to get some, feel free to join my page

Mauigerbil (author)2012-08-26

Lol my friend got a fiddler crab for her birthday from a friend and she had NO IDEA how to take care of one. She put it in a full fishbowl with sand, and then with further online research, she found out it was slowly dying in there, so she drained it to just a little water and a rock. She hates that thing like the plague and is her least favorite present. Poor girl..

At least her friend didn't get her more than one or else stating it would be awkward..

Mauigerbil (author)Mauigerbil2012-08-26

Also why is it tagged under tacos?

aquilusdomini (author)2012-04-06

I'm very glad this little bit on crabs was posted. I just rescued my fiddler crab from the wrath of Walmart. Apparently they don't feed the crabs because they do not sell what these crabs need to eat and they also keep the poor creatures confined in small plastic dishes with pebbles and a small amount of water in the bottom. Tomorrow i'm going to get the tank and all the recommended accessories and chlorine removers/aquarium salt. Once this little fella (i named him Bob) gets settled, i'll go back and save the others. That's a real nice example tank in the picture here and i hope to set mine up similar to it. For future reference to anyone who has ever considered purchasing an aquatic animal at Walmart, it probably hasn't eaten, slept, or had adequate housing for quite some time so don't be broken hearted if the poor dear dies the day after you bring it home. I saved a dwarf aquatic frog from there once (it was in the same kind of small plastic dish as the crab), gave it a nice large bowl and some food but he/she died the next day. Most of these stores do not feed these animals because they don't know what they eat and apparently they don't know how to keep them housed either. So yeah, just thought i'd throw that out there.

rush2ady (author)aquilusdomini2012-07-23

I've also seen tons of dead fish at the Walmart. Absolutely pathetic inhumane care they give to their animals. I'm not sure purchasing the poor creatures is the best route, Walmart will simply respond by restocking them with more helpless creatures and being satisfied that their "products" are being sold. Maybe filing complaints with your local humane society or other authority would be more productive in getting Walmart to change its practices.

aquilusdomini (author)rush2ady2012-07-24

Indeed, walmart is terrible and i know that they will restock if i purchase the animals however those animals deserve some kind of a life away from the store shelf and it's against my very being to leave them there to die. Sadly, our local humane society is worthless. They do not do rescues or work for the "lesser" creatures such as fish and invertebrates. It's difficult to even get a horse/dog/cat abuser prosecuted here. I live in a very "conservative" town where animals take a back seat to guns, "god" and human enjoyment. The dogs and cats from our pounds are still sent to animal research facilities because the city council voted to let it continue even though many, including i, protested the decision. Every spring and autumn there is a deer cull (they hire snipers to come in and take out roughly 80 deer, which include fawns, adult males and adult females) in our two wooded/marshland parks because people complained of deer in their gardens. Illegal hunting is overlooked as well. This is the expected extreme behaviour of my town, which is sadly considered the "birthplace of the republican party" and one of Ted Nugent's home towns. Jackson, MI is not a nice place to live for animals or those that care about animals. If i could get national attention for the atrocities of this town i would gladly do so. But the problem is, who will listen and who will not be bribed or bought off?

In the end though, i'm glad i saved the fiddler crabs from the walmart. They do restock them after the others die on the shelves. A couple weeks ago i noticed they were carrying purple clawed fiddlers. Such beautiful little creatures. Perhaps i could, maybe, just maybe get through to the pet department manager to post how to properly care for the fiddlers so that at least when people buy them, they know how to care for them.

mateo melchor (author)2012-02-28

how much sea salt do I add to a 1 gallon tank and one fiddler crab

RedneckAsian (author)2010-06-22

What ratio should the brackish water be?

halo99 (author)RedneckAsian2010-06-24

Depending on how big your tank is brackish water is just a fancy word for salt water so for a 5 gal i would put in half a teaspoon heres a website for you,%20Fiddler%20Crabs.htm

desreydel (author)halo992010-09-15

(I couldn't start a new comment so I decided to just reply.) I was wondering about your internal filter. I don't currently have a filter for my fiddlers, can you share the name or brand of yours? Also, is it a cordless filter? i'm curious. And where did you find those tunnels? I would prefer to get something more natural looking to camoflauge with my tank, but at this point I haven't found anything yet. Thanks in advance

zackatron (author)desreydel2011-03-10

he has a whisper internal filter and looks like pvc joints

halo99 (author)desreydel2010-11-30

Sorry I didn't reply sooner,I didn't see any new comments on my inbox. Should I still answer your questions because I don't want to tell you something you already know.

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