SPS corals always have hard skeletons and very small polyps - usually not much bigger than a pin head though there is no set size requirement. To the new hobbyist SPS corals such as Acropora, Montiporas, and Bird's Nest can be somewhat intimidating. These stony corals come in an incredible variety of colors and growth forms that can be absolutely stunning. However, their care requirements are generally a step or two above the usual beginner corals like softies and LPS.
Moderate to intense lighting, good random flow, and clean, stable water quality are key with these corals. Properly maintained they can grow quite quickly. Growth forms include branching, plating, and encrusting varieties.