Well, I know some because I have one, and for one, the 'Answer' was a question. See other 'posts' to mantain the balance of the society, of lower-numbered questions.
A lot
they need land and water
No, Hermit Crabs and Fiddler crabs require two different environments. The Hermit Crab would drown in the water a Fiddler Crab needs. You can always ask your local pet store if there is any way possible though. Some hermit crabs live on land others live in water even land hermit need two enter salt water , fiddler crabs are brackish or fresh hermit crabs can't breathe in those environments
you kill the fiddler crab
It's hard to know how much a fiddler crab weighs because there are many different types. But I do know that a fiddler crab's large claw weighs about half of it's body weight.
No crabs cannot live in a tropical tank. If you go to a petstore they will try to sell you small fiddler crabs, however they do not live in freshwater, they live in brackish water like most small crabs. All brackish water crabs need to be able to be out of water for a certain period of time. If you do buy one of these crabs and put them in your tank they will only be able to survive around a month.
You can make salt water for fiddler crabs. You need to use sea salt. Never use table salt. And you need to use distilled water or water that has been treated to remove the chlorine. You can get sea salt at a pet store. 1 tea salt to 1 gallon water. Change it often.
The kind of hermit crabs most people think of are Land Hermit Crabs. They live on land, and need at least enough water to submerge themselves. Land Hermit Crabs do need sea salt to keep their body chemistry balanced, and as such, need access to both salt and fresh water. Marine Hermit Crabs require a full saltwater aquarium to survive. Such tanks are elaborate, and should be researched thoroughly before purchase. Saltwater pets of all sorts are often regarded as difficult to care for.
they cannot live in either amigo they MUST have land to walk around on so unless you have a rock,plant,etc. that sticks out of the water i am sorry
Well you can give them tap water but you need a sponge. Fill it with water, nice and full and set it in your crabs cage.
Fiddler crabs come from the mangroves where there may be a regular fresh water flush so they may survive for a short while in fresh water. They will not however be able to live for long because they need the calcium and other elements in sea water in order for them to get the neccessities for shell growth.
yes
Hermit crabs do need both types of water but they need both water because they need to clean themselves and they just drink salt water.