Fiddler Crab Care





Introduction: 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

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

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

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

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

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.


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...



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    56 Discussions

    I have a 5 gallon tank. So how many fiddler crabs could I get?

    I soon hope to have Fiddler Crabs I have a 20 gallon tank. I was wondering how many males/females I should get and I go up north with my family sometimes on Friday night and get back home Sunday night. Is there a way to keep them home and have like a fish feeder tablet to feed them?

    I just totally researched crab care, now I discovered I should not have two males. but my husband wanted two males and a female. I did not know they turn upside down. He thought she died because she was upside down floating. He flushed her. tear tear. Anyway both of my male fiddler crabs are molting. They have been for at least a week and a half. How long will it take before they come out? Also I read that I don't have to worry about anything except ensure they have a new shell available. Wouldn't that be a hermit crab?

    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!!!????

    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?

    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 !

    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 !

    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?

    2 replies

    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

    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?

    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.

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

    2 replies

    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.

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

    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 !!!

    1 reply

    2 years ago

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

    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?

    1 reply

    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.

    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