Reef
The reef aquarium is a delicate set-up since live reef building corals has very high demands when it comes to water quality, lighting and currents. They are usually attempted by aquarists with plenty of experience from both freshwater aquariums and easier marine set-ups. Some reef aquariums contain fish, while others focus solely on corals and other invertebrates. The focal point of reef tanks are usually different types of hard and soft corals, plus reef associated invertebrates like the delicate anemones. Some aquarists like to mimic a certain reef, e.g. the Great Barrier Reef off the coast of Australia, while others go for a more eclectic tank with species from many different parts of the world. Since corals and many other reef species are stationary they rely on currents to bring them food and rid them of waste products. This means that you have to design the water movements in your reef aquarium well if you want the inhabitants to thrive. Currents are also necessary for their reproduction. Always research which type of water movements a species need before you add it, since different parts of the reef are subjected to different water actions. Some species need the waves and surf of the upper reef environment while others prefer far less boisterous currents.
