Saltwater aquariums should generally contain fewer fish than fresh water tanks, because the species tend to grow bigger in size. Marine species may be bred in a captive environment, or caught in the wild. Captive bred species are easier to care for and usually hardier than caught species. It generates a great amount of stress for a fish to be captured in the wild and then introduced into an aquarium environment. It is often difficult for them to figure out how to eat. Whenever possible, purchase your fish from a retailer that deals only with breeders or from the breeders themselves. There are five different types of saltwater aquariums.
The first type of saltwater aquarium is the fish only aquarium. This is probably the easiest to care for of the five types, simply because you are only dealing with one type of species. Amongst the saltwater fish there are both tropical and coldwater types. They can’t be kept together for obvious reasons. The water temperatures vary greatly. Tropical fish are usually brighter in color, and therefore more appealing to aquarium