No they can not as crabs will use claws to catch and harm them.
1000
test it out and youll see
I'd say no more than 6 medium sized crabs in a 55 gallon tank.
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.
yes definately!
i suppose they could fit, but they need lots of room to move around in. So a ten gallon tank would be the smallest size for two hermit crabs to live in
Well for the safety of your hermit crabs i would use the basic rule of 1gallon of tank space per hermit crab..... so you could get any size you want.... but lets say you had a 10gallon tank so you could have 10 hermit crabs in the same tank.
yes, at least with some types of crabs. clowns will do well with hermit crabs, though I'm unsure with other varieties. clown fish naturally live with crabs, but they may need an anemone if it is a particularly aggressive crab.
well you can control the pressure of it but by level, that depends on how much oxygen is in the tank. the easiest way to change the pressure of oxygen can be by heating or cooling the tank.
it could live in a tank by its self
They can live up to 2 years old with sea salt, a big tank and plenty of water.