Aquariums can be made into a habitat that is suitable to both salt water and fresh water, but your choice on how an aquarium is used has big consequences.
Salt water fish tend to be larger fish, which for many people is a good thing. If you don’t have the space for a large aquarium though, this could limit your ability to purchase a large number of fish.
With a salt water fish tank, your filtration systems need to be able to contend with the abrasive and corrosive nature of salt. With a fresh water fish tank, the demands of a filtration system are far lower and therefore far cheaper.
Fresh water fish tend to be smaller than their salt water counterparts, which means that you can have as many fish in a smaller fish tank. For many people, because of this and the lower costs associated with caring for them, fresh water aquariums are ideal.
