Coral Identification

There are over 50 species of reef-building (hard) corals in the western Atlantic. They form colonies (a group of polyps) of characteristic shape, size, and color. However, corals are very dynamic and the same species can exhibit morphological differences due to local conditions.

In general, coral colonies exhibit three basic growth forms; branching, massive, and plate-like.

Corals are divided into two classes, hydrozoans (fire corals) and anthozoans (hard and soft corals).

Fire corals are common in shallow tropical waters to about 30 meters. These corals resemble hard corals. Most commonly, they have blade-like or branching growth forms. Fire corals can even encrust octocorals (soft corals), such as sea fans. The colony is usually yellowish to brownish with pale, white tips. If you brush up against it, you'll understand why it received the name fire or stinging coral.

Anthozoan corals are further divided into two primary subclasses, octocorals (soft corals) and hexacorals (hard corals). Octocorals are soft corals, such as sea fans, sea whips, and sea plumes. Soft corals have a flexible skeleton, as opposed to a stony skeleton. Hexacorals include hard, reef-building corals. These are the corals that people are most familiar with. Hard corals are the primary reef-builders. The white skeletons are covered with a thin layer of tissue which gives the coral its color, from yellow to green to pink.