- Hard corals are more colourful than soft corals and named so because they build a hard skeleton which then remains after death. These then become building blocks of coral reefs.
- Elkhorn coral and pillar coral are two examples of hard corals.
- Hard corals are of two types: LPS and SPS. Which stand for large polyp stony and small polyp stony, though LPS are sometimes referred to as long polyp stony. Sometimes the last ‘s’ in LPS and SPS is also referred to as scleractinian so small polyp scleractinian, as all hard corals, belong to the order Scleractinia.