Sea Fans are fan-shaped soft corals growing in a vertical plane. They are highly branched with delicate lace-like patterns. For example, Gorgonia ventalina and Iciligorgia schrammi. Sea Whips have long, thin stalks resembling whips. If branched, the branches normally occur near the base, such as Ellisellidae species and Pterogorgia species.
Hard corals are the most significant group of corals in terms of reef building.
As the coral grows, the polyps secrete a massive external skeleton of calcium carbonate commonly known as limestone. Hard corals can be grouped into the following categories. Pillar or branching coral - These corals grow in the form of a cylinder or spiral. Colonies show a variety of growth patterns including huge mountains, domes, boulders, multi-lobed heads or knobs. These corals include Porites asteroides, Montastrea spp.