Their mutualistic relationships with reef-building corals form the basis of a highly diverse and productive ecosystem.

These reef-building corals largely depend on them.

The reef-building corals are polyp-colonies, strengthened by the formation of a firm skeleton.

Also about 600 species of reef-building coral - the latter equal to 75 percent of the world's known total.

Reproduction in fire corals is more complex than in other reef-building corals.

The tropical setting and warm clear waters give it about 580 of the world's 793 species of reef-building corals.

This species of reef-building coral has a hemispherical, brain-like shape with a brown, yellow, or gray colour.

The island is even said to have one of the world's largest concentrations of reef-building corals.

Meanwhile, Mootfowl and his group were ever at work as the city's structures took their places one upon the other, faster than reef-building corals.

This group includes reef-building corals (scleractinians), sea anemones and zoanthids.