Fiddler crab care?

Question

Hi, I just bought a mini crab from Petsmart, and a guy there told me it was ok to keep with my other fish if I gave it some land to crawl on, which it has. I looked it up online and found out it was a fiddler crab, and some of the websites said that it does best in brackish water.
I've only had it for a a few days, but it is healthy and is doing a good job cleaning debris in my tank and has left my fish alone, and I would like to be able to keep it. Does anyone know if the crab can be kept in freshwater at all, or if I should return it, and if I can keep it, does it have any other special water requirements? Also, if I do need to return it, are there any other small freshwater crabs that won't harm my fish?
thanks for any advice

Answer 1

If you keep it in freshwater, it will be slowly dying. The crabs are specifically adapted to brackish environments, and a long term change in something as paramount as salinity is fatal. It may live for a month or two in freshwater, but it will be on its way out... Also, it will attack small, slow moving fish, and may eat fish at night when they rest... It would really be best if you just gave it back.

Soop Nazi

Answer 2

They do need to have some salt in their water. And this should be marine salt, like what's used in saltwater aquaria, not table or aquarium salt (for freshwater fish). The reason being, there are minerals in the seawater that the crabs need for molting their shells. They also need to have a higher pH and hardness than regular tapwater. If they don't get these, their shells will slowly soften, and they die.

There are no crabs (fiddlers or red claws included) that can be kept in freshwater without some salt.

Now, depending on the types of fish you have, they may not mind a small amount of salt in their water. Guppies and mollies in particular should have some salt and a higher water hardness, so they would do well in the same conditions a fiddler crab needs. Any livebearer could, for that matter, but guppies and mollies can tolerate more salt than most. Tetras, on the other hand, won't tolerate very much.

Your fish may have been able to avoid your crab so far, but the crabs usually will eat smaller fish - if not, the will at the least attach their fins in the attempt to catch them (especially at night when they are at rest).

Rather than a crab, if you're like to try invertebrates, there is a dwarf crayfish that's fish-safe, and a variety of shrimp (that come in sizes from about an inch to several inches long) that are sold. Since you have fish, I'd avoid any of the longarm shrimp which can be predatory. You'd still need to give them hiding places where they can molt their exoskeletons, because until the new one hardens, they can be harassed by your fish and killed.

See these link for ifo in fiddler crabs and other inverts:
http://www.freewebs.com/fiddlercrabcare/
http://www.petshrimp.com/shrimpspecies.html
http://www.shrimpcrabsandcrayfish.co.uk/Shrimp.htm?Caridina.htm~mainFrame

Answer 3

Taking care of your fiddler crab is not a difficult job. The first consideration is where the crab or crabs will be housed. You can fit three to five mid sized crabs in a 10 gallon aquarium. Build sandy slopes in the aquarium to give them a place to burrow. They also need lost of dry sand and rock areas that mimic their natural habitat.

Some salt in the water is essential to recreating the brackish water environment fiddler crabs are accustomed to. Check the mixing requirements on the aquarium salt you purchase for preparation instructions. Without brackish water, your crabs may not be with you for a long time. An average water temperature of around 74-84 F would make your pets feel right at home.

The fiddler crab, enjoys feeding off of death and destruction. Dead fish, algae, and other such organic matter is a special treat. This doesn't mean that you don't have to feed them. After all, if you keep a fairly clean aquarium, there may not be enough waste to feed on. So what do you feed scavengers? Your pet food store has an excellent choice of food specifically for your crabs. Ask for suggestions on seaweed, fresh fish, and dried shrimps. Do not overfeed.

Check the aquarium water quality regularly. There are some very useful kits available for this purpose. Aim for the standard acidity of 8.0 to 8.2. Testing, cleaning and changing the water in your aquarium all contribute to a pleasant environment for your pet crabs

Keeping and caring for your fiddler crab will provide you with many rewards, in the joy of watching these beautiful creatures, coexist within a carefully recreated environment, learning about them and their habits and watching them flourish.