A reef aquarium or reef tank is a marine aquarium that prominently displays live corals and other marine invertebrates as well as fish that play a role in maintaining the tropical coral reef environment. A reef aquarium requires appropriately intense lighting, turbulent water movement, and more stable water chemistry than fish-only marine aquaria, and careful consideration is given to which reef animals are appropriate and compatible with each other.
Reef aquariums consist of a number of components, in addition to the livestock, including:
Display tank: The primary tank in which the livestock are kept and shown.
Stand: A stand allows for placement of the display tank at eye level and provides space for storage of the accessory components.
Sump: An accessory tank in which mechanical equipment is kept. A remote sump allows for a clutter-free display tank.
Refugium: An accessory tank dedicated to the cultivation of beneficial macroalgae and microflora/fauna. The refugium and sump are often housed in a single tank with a system of dividers to separate the compartments.