There are almost 15,000 species of marine fish. The appearance, nutritional requirements, environmental needs, reproduction, compatibility with other marine creatures, and survival adaptations of these different species vary remarkably. To successfully maintain an aquarium, the aquarist needs to understand all of these aspects of a fish before considering adding the fish to the tank. Understanding these characteristics of a fish before acquiring it, and knowing from where it was obtained, is necessary to provide the conditions in which the fish can thrive. Also be aware that a fish may have multiple common names, and multiple fish may have the same name. Comparing the genus and species of the fish may help avoid some confusion. Consult our compatibility chart to help you choose marine fish that will live well with each other.