Depending on the species and its diet, they can live for at least a year or two, and some even longer. Aquarium crabs in saltwater tanks should not be kept if they become too large.
Over 100 Years.
It all depends on what species of lobster and crab your talking about. In general if your referring to the standard lobster and crab that end up on our plate for dinner, then yes you can have both of them in an aquarium as long as its big enough.
A Hermit crab can live up to 100 years of age
It depends on what kind of fish, and the size of the aquarium.
It depends.
they can't
In an aquarium full of dead fish or in the dead sea :)
10 years
Stone crab have a life span of 7 to 8 years.
it will appear by and underneath the aquarium
1 year
2 years
for 2 years at the longest