CorallimorphariaCorallimorpharia

Corallimorpharians are marine cnidarians related to stony corals, though they lack a stony skeleton. These polyps typically have a broad, flat oral disc, often wider than their column, fringed with short, radiating tentacles. Oral discs range from 1 cm (0.4 in) to over 30 cm (12 in) in diameter. Their colouration varies widely, from drab browns and greens to bright reds, blues, and purples, sometimes with iridescent qualities.

They occur across a wide range of habitats, from shallow reef crests and lagoons to deeper reef slopes, attaching to hard substrates, rubble, or dead coral. These polyps live at depths typically between 1-50 m (3-165 ft). Corallimorpharians are opportunistic predators, capturing zooplankton and small invertebrates. They can be found as solitary individuals or forming dense, carpet-like aggregations that overgrow significant reef areas, occasionally contributing to shifts from hard coral to soft coral dominance. Divers commonly encounter them on many reefs.