When setting up a salt water fish tank, one of the first things that a new hobbyist should consider is what types of fish they want, or what other types of animals they want to keep. Some people choose to purchase live coral for their fish tanks and don't even purchase any fish at all, for example, while others prefer a mix of fish and coral. Some people just stick to a few salt water fish species and no coral, and some people prefer a huge mix of diverse species. This must be decided ahead of time, though, since the filtration, lighting, chemistry and overall expense will largely be determined by this decision. The common way of setting up a salt water fish tank is with fish only, which is usually a very easy way for new hobbyists to be successful, as long as they purchase some of the hardier and less expensive species at least when they're starting out.
Setting up a salt water fish tank is not too much different than it would be for fresh water, although salt mix, crushed coral gravel, and a hydrometer must be added. Salt water fish species do not tend to extract much in the way of calcium or other elements directly from the water, so no special chemical additives are generally required other than those in the salt mix. Many people prefer setting up a salt water fish tank with a mini coral reef environment, which is a bit more complicated but it is beautiful and growing in popularity. Live coral and other invertebrates that contain symbiotic algae require much more light than fish or other invertebrates do, and there are several other additions that this type of tank requires. It's also best to keep the number of salt water fish species to a minimum in this type of tank, although many invertebrates, including coral, polyps, shrimp, starfish, clams, and so on can be kept. Compatibility is a bigger concern with live coral, so many people just skip the fish altogether.
