This fan is usually seen on vertical walls of the outer reef in depths between 10-30 m (33-100 ft). The colonies form an intricate network of rectangular meshes, attaining their largest size and most spectacular growth forms in places where currents are especially strong. In prime positions these fan are up to 2-3 m (6-10ft) high and measure more than 3-4 m (10-13 ft)in width. The fans invariably project form the reef's surface at angles offering maximum exposure to the prevailing current, which supplies nourishment in the form of plankton. Color usually ranges form cream to pale pinkish orange. One variety's red color is due to a thin algal coating. Alcyonarians rarely harbor encrusting organisms such as algae, sponges, and sea squirts, as their abundant feeding polyps and various chemical researchers are analyzing the chemical makeup of these species, in an attempt to discover substances that will inhibit cancer and other diseases.
The long, fleshy polyps of this species, and other members of the genus Goniopra, resemble some soft corals, but the stalked tientacles are actually attached to a hard coral skeleton. When the polyps are fully expanded, the skeleton is completely obscured. About 15-20 species of Goniopra are found in the southeast Asian region. These and other species of hard corals thrive in shallow, warm seas. Most are common in the turbid waters of lagoons and on coastal reefs where wave action is minimal. These corals are very aggressive towards other coral species, their long sweeping tentacles usually destroying any neighboring colonies within reach. Most depend on bright sunlight for optimal growth, and the abundance of hard and soft corals gradually diminishes with increasing depth. Relatively few species occur below depths of 20-30 m (66-100ft). Many of the deep water corals do not have symbiotic algae living in their tissues, and therefore must provide their own nutrition by capturing planktonic food.
