Exotic Pets: How to Care for Fiddler Crabs

Are you tired of watching boring-looking fish seem to sit there all day? Their color was flashy at first, but when it comes down to it, they're just boring. Want to try a new, or even exotic pet that'll be a lot more fun for you and your guests?

Try a fiddler crab! They're about as cheap as any beta or goldfish and can be found at many pet stores, ranging from $2-$6, but they're infinitely more entertaining.

My wife and I decided to try them just because we were looking for other pet supplies, saw them in the tank, thought they looked really funny, and saw they were cheap. Why not?

A fiddler crab can be found with their bodies at about ½" size (babies) and can grow up to about 1". What sets them apart is that for males one of their two major claws is HUGE! It can be either their left one or their right one (we managed to get one of each - much easier to identify). Females have two small claws, so we didn't bother with a female. There are also many different species of fiddler crabs with slight variations in color, but they're mostly brownish/blackish and orange.

Also, fiddler crabs are very sociable creatures, with a wide variety of behavior that makes watching them a blast! That's what attracted us to them. In an attempt to attract mates, they wave their claws around almost as if they're dancing. Sometimes they'll do it for hours on end and they'll do it for a little while at least every day.

Unfortunately, the pet store owner didn't give us much information about them. After a really close-call with one of them, we scoured the internet to see what information we could find about taking good care of them. As it turns out, they are very simple to care for, with just a few helpful tips.

First off, I'd recommend getting two of them. While I'm sure one of them is still very enjoyable, watching two of them engaged in territorial disputes is much more entertaining. They often grapple claws and push each other back and forth, underwater and above water. Although you may be worried about them fighting, it seems to be more of a ceremonial thing and they never do any real damage to each other.

It is recommended to have at least one square foot of space for each crab. This way, they'll have plenty of room to explore and establish territories, but they'll still run into each other and fight once in a while. Having other creatures in the same aquarium doesn't seem to bother their territories or their sense of space. They don't often seem to realize the other creatures exist.

One thing a pet-store owner might not tell you is that fiddler crabs need a place to get out of the water and sit on land. I've read on the internet that if you don't give them space to get out of the water, they'll climb up your filter right out of your tank. Though they could climb out of our tank with tubes/etc., they haven't tried because we give them plenty of space to get out of the water.

There's two ways you can give your crabs land area. If you're just raising fiddler crabs, you can slope your gravel up to one side and fill the other side with water. This makes a beach for them and it's easy for you and for them.

Or, you can fill your tank up about ½ to ¾ with water (especially if you want other creatures in there with them - we have two fire newts). Then, you'll need to place objects they can crawl up and reach the surface. We've done several things: a stack of rocks, a piece of coral which leads up to a suspended bamboo raft, and an aquarium palm-tree with only the top sticking out of the water. We put a plant in there for decoration, but it turns out they can even climb to the top of it to get above the water!

One thing we've found you can't neglect is the type of water you give them. As with any creature, you'll want to de-chlorinate the water. You can just put it in a pitcher and let the chlorine evaporate over 24 hrs. or you can buy de-chlorinating water drops that are much quicker.

Now, the pet store we got it from said that fresh water was sufficient. After a few weeks, one of our fiddler crabs lost a few legs and the other crab almost died. Through internet research we learned what he was missing: salt in the water!

That's not to say that they need saltwater. If you gave them regular saltwater like the ocean, they'd die just as fast (or faster) than giving them plain tap water. What they need is brackish water: regular water with about 1/5as much salt as normal salt water.

When our crab almost died (he was slowing down so much that when he'd try to climb something, he'd just flip over on his back and twitch), we quickly made a salt solution with non-iodized salt, put him in his own bucket, and dumped it straight on him. That woke him up quick! We let him sit in that salt solution for two days while we bought aquarium salt and added more to the tank. Since then, our crabs have been as healthy as they could be!

You can get either sea salt or aquarium "conditioning" salt. If you use the sea salt, just follow it's directions for making regular saltwater, but put in only about 1/5 what the directions tell you. The salt is also supposed to help any other creatures in your tank by providing minerals they need and increasing their slime coat, which helps them stay strong. Our newts are doing just great with the extra salt and even seem more lively.

Your crabs should molt about 1 or 2 times a year. This is a good thing and if they happened to lose any limbs before that, they will start growing them back. Also, you should leave their molted exoskeleton in the water for them for at least a week. They'll chew on it and replenish much of the calcium they need to harden their fresh shell.

Finally, the easy part: diet! Fiddler crabs will eat pretty much anything. If they're not climbing something or waving their claw during their mating dance, they're scavenging the bottom of the aquarium looking for food. The truth is, they can eat pretty much anything. As scavengers, they hardly ever catch live prey, but if you drop a live snail in there, they'll definitely eat it.

One of ours really likes chewing on the plant we just put in there and they both love to eat any algae that's growing. We sometimes put dead crickets in there for the newts, but if they notice, the crabs will try to get them first and they seem to love those more than anything. You can also feed them sinking shrimp pellets which they love to eat when they find them. Any food matter they find, they'll eat.

Your fiddler crabs will pick up any organic matter they find, but they're not enough to keep the tank clean. If you don't want it to stink or you don't want to clean their water every week, you definitely should get a water filter. They're pretty inexpensive and you just rinse the filter off every week or two and it'll do a pretty good job.

That's it! The two most important things you need to remember is to give them a place to climb out of the water and use brackish water (about 1/5 that of salt water). Those things are easy to do, but essential. You'll find raising fiddler crabs to be a piece of cake and incredibly enjoyable. They're always fun to watch and they're sure to impress your guests! I hope you found this information useful, and if you want to know anything else, just ask.