Blister Coral

About

Blister Coral (Horastrea indica) is an uncommon large-polyp stony coral from the western Indian Ocean, found across a relatively narrow geographic range along the eastern African coast and nearby island systems. In the wild it settles on sandy reef areas, growing into broad, domed colonies that can develop a rounded to slightly irregular hemispherical form over time. The individual corallites are large and distinctly plocoid, meaning each polyp occupies its own defined skeletal cup, though mature colonies often show a tendency toward meandering rows with multiple centers, giving older specimens a more complex, labyrinthine texture. The septa and costae are well developed and visible to the naked eye, giving the skeleton a bold, sculptural quality. Coloration is a muted pale brown overall, contrasted by blue-grey oral discs that lend the coral a subtle, cool-toned appearance. Horastrea indica is a monotypic genus, meaning it stands completely alone with no close relatives in the same group, which makes it something of a curiosity for coral enthusiasts. In the aquarium it needs high light and moderate flow to thrive. It is considered an intermediate-level coral. Not the most demanding species around, but it rewards keepers who pay attention to water quality and stable conditions.