Does anyone know anything about Fiddler Crabs?

Question

I just got back from the beach and caught two fiddler crabs, I have them in a small tank with some rocks and filled with salt water straight from their home. If you have any helpful tips or know ANYTHING about them please dont hesitate to reply! Thanks!

Answer 1

All i know is they cannot play the fiddle!

Answer 2

Here is a bit of useful info:

http://exoticpets.about.com/od/fiddlercrabs/Fiddle_Crabs.htm



Fiddler crabs are interesting tiny creatures that are found in brackish waters, either in mud or sand. They don't ever grow much over two inches from the end of one leg to the end of the opposite leg on the other side of its shell. The male has one claw that seems far too huge for his body. He waves it about to ward off enemies and to attract females. In the aquarium they are happiest in pairs, as sometimes one female will kill extra crabs in her tank. This is less likely to happen in very large tanks. It is recommended to house them in at least a ten gallon tank. They do not thrive as single pets.





Fiddler crabs are often sold in pet shops as freshwater inhabitants. While in the stores they may be kept entirely underwater, and their water will contain no salt. Unfortunately for the crabs, they cannot live this way for long, and in under a month you can expect a fiddler kept in such conditions to die.









Fiddler crabs must have access to dry land, as well as slightly salty water. They spend part of their time under the water, and part of their time out on the sand. The simplest solution is to line the aquarium with three to six inches of aquarium sand. Aquarium gravel will work, too, but they cannot tunnel through it as easily.



Pile it 6" to 8" high in one end, but not so high that the crabs can reach the top of the tank, because they will escape. Make the other end no deeper than an inch. Create a slope on which they can climb. Place a cup or bowl in the shallow end and slowly fill the tank with water until only about 1" of the high end of the sand beach is exposed.





Add dechloraminator to the water if you use tap water. Next add about one tablespoon of kosher salt or two tablespoons of rock salt to the tank. Filtration is optional.





You will need to top the tank off with new water every week or so to replace evaporated water, but do not add more salt. The salt will not evaporate at the same rate as the water, and your crabs will still have enough.





Crabs are not affectionate pets, but they are quite interesting to watch. The little male waves his giant claw about in a semaphore like fashion when you approach, or when he wants to impress the lady crab. The crabs will dig tunnels in the sand and they may scuttle into them to hide if you're not very stealthy.





Fiddler crabs eat microscopic critters that show up in the sand as well as algae. The female crams food into her mouth one tiny claw after the other, but the male cannot eat with his large claw and must feed himself solely with the little one. The crabs sift the sand through their systems and get nourishment from the microscopic particles and bacteria in it.





Periodically the crabs will shed their shells. As they ease themselves out of their old shell that has grown too small, you can see a whole new set of eight legs and two claws curled up inside. If they lose a leg or claw it will grow back inside the shell and be ready the next time they molt. If the male loses his large claw, when he molts the big claw will be on the opposite side from where it was. They must be careful for a few days until the new shell hardens.





Some aquarists remove the shells from the water, but this is not advised. The crabs will consume the old shell over several days and it will provide them with the calcium they need to develop a hard new shell. If the old shell remains in the water for more than a week, it may be removed, but it is unlikely that this will be a problem.

Answer 3

“Uca” comes from the name the local Seminoles called the little scudders. We call them “fiddlers” because that big claw the males wave around looks exactly like the 1684 Stradivarius mini-violin that Antonio Stradivari made for his second son – the one who played second fiddle.

Male fiddler crabs dig deep burrows in the mud. When the tide approaches (twice a day), they pull a lid over their burrow and retreat into the safety of their little hidey-holes. As the water withdraws, they flip their lids and start looking for algae and fiddler babes. When they see a female, they start waving that big claw around and making kissy-kissy noises (actually, rattling their big claw against their burrow walls) in hopes of coaxing one of the nubile female crabs into their boudoir to look at their etchings.Female fiddler crabs also dig burrows and come out when the tide recedes to look for algae and guys with big claws.

Big wading birds love tasty little fiddler crabs. Turtles ditto. Also raccoons and big frogs and toads. Not too many restaurants tho serve fiddler crabs on their menu. Indoors, their main threat is climbing out and drying out.



Add a teaspoon of salt per gallon of water. Change your fiddler crab water often.

Male fiddler crabs seek out high points in their cage so they can wave at more females. They can also climb out of their cage unless you cover it securely.

We call them mini-crabs because they top out at about 1.5 inches – plus that great big claw on the male fiddler crabs.

Most important, provide their food in a shallow dish – one they can get in and out of easily. Hermit crab food works great. Probably anything you give them will work. Change their food daily. Once most foods get wet, they start growing moldy and … oh, wait, they eat that too. But you want a cage that smells clean, so change their food daily. You for sure want to avoid providing a home for those pesky gnat-like flitterbys that always find smelly food. Fiddler crabs eat surprisingly daintily. They pick up each tiny speck of food and carefully place it into their mouths -- unlike the larger crabs that greedily grab the biggest chunks they can find and run off with them.



Space Requirements: In small groups your fiddler crabs will want a square foot of space each. When you crowd them like we do, they seem to lose interest in arguing. They’ll act more naturally (argue more) in smaller herds.



Breeding: If the male fiddler crab coaxed a female into his burrow for a two-week honeymoon, she will produce numerous eggs (in the thousands) that drift off into the ocean. Hard to duplicate in the average backyard.



Substrate Choice: Dirt, coconut fiber, potting soil, or vermiculite would make a good substrate to burrow into. Most people use gravel or sand. Fiddler crabs blend into natural gravels.



Mini-Caves. Since few cages are tall enough to provide two feet of substrate to burrow into, you may want to give your fiddler crab a mini-cave or at least an object to dig under.



Tank Mates: You can mix them with equal-sized non-violent terrarium residents. Anoles, fire-belly toads, newts, dwarf African frogs come to mind. Even tho those big claws look formidable, these guys are not crayfish. You can pick them up with impunity (or with a net if you are fresh out of impunity). Cover your net. Fiddler crabs skitter out of a net in an instamante.



Immaterial to the crabs, but planted tanks (even plastic plants) make their biotope look better to us. Feng shui does not seem to apply to fiddler crabs.