Small Polyp Stony Corals
Small polyp stony corals (SPS) are what many people think of as the conventional reef-building corals. As a group, they are some of the most beautiful and some of the most difficult to keep, often requiring high flow rates, intense lighting and optimal, stable water chemistry.
Probably the most popular family of small polyp stony corals (SPS) seen in the hobby are members of Acroporidae, which includes species from both Acropora and Montipora genuses. While it is impossible to provide comprehensive care information for such a broad characterization of coral, there are some general items to consider that could potentially be helpful when considering the husbandry requirements of these corals.
One rule of thumb to consider involves guestimating flow rate requirements: small polyp stony corals (SPS) with thin branches are generally from habitats with moderate flow, while small polyp stony corals (SPS) with thick, sturdy branches are often from habitats with higher flow rates. Keep in mind that water flow in the ocean is typically turbulent, not laminar, so try to recreate a turbulent flow pattern in your aquarium by equipping a surge device or by properly arranging the power-heads (pumps) to cross flows and create a swirling current.
Another rule of thumb that can be considered is how to approximate light intensity requirements. The proxy often used to judge lighting requirements for small polyp stony corals (SPS) is the color of the coral specimen itself. Brightly colored corals are generally thought to originate in higher light intensity environments (shallow water), whereas the more drably colored specimens are thought to originate in lower light intensity environments (deeper water). As a rough rule of thumb, therefore, darker corals are often considered to have relatively lower lighting requirements than their fluorescent, vibrantly colored cousins. To be fair, however, even the most brightly colored corals will ‘brown-out’ under sub-optimal lighting conditions. Since small polyp stony (SPS) coral color can vary based on the individual circumstances of the specimen in question—it should only be used as a rough gauge for light requirements and a jumping off point to research and understand the individual species husbandry requirements.
Acropora–one of the most popular Small Polyp Stony Corals (SPS)
Montipora–one of the most prolific small polyp stony corals (SPS)
Saltwater Aquarium Blog Tip: Even though the coral you purchased may require intense lighting, it is always best to start slowly and gradually acclimate the small polyp stony coral (SPS) to the light intensity in your aquarium, starting first at the bottom of the aquarium and slowly working your way up over time. If you move too quickly, you risk shocking the coral which may cause you to lose the entire specimen.
Advanced Aquarist Note: While most small polyp stony corals possess symbiotic zooxanthellae, and derive significant nutrition from photosynthesis (hence the intense lighting requirement) many species possess polyps that are capable of capturing suitably sized prey. To boost coral growth, consider adding phytoplankton, rotifers, oyster eggs or copepod naupli as a nutritional supplement. It is best to research the size of prey your coral are adept at capturing and tailor your supplementation to feeding prey of that size.
Learn more about the other types of popular aquarium corals:
For more information about small polyp stony corals, check out the following resources:
Scleractinia (the group of stony corals)
Shop for small polyp stony corals on Live Aquaria