There are three cycles of septa (stony ridges) inside the calyx and these continue as well-developed costae between the corallites.

This is a zooxanthellate species containing microscopic symbiotic algae in the tissues which supplement the nutritional needs of the colony.

[4][6] H. indica is found in the southwestern Indian Ocean, its range extending from Somalia, Kenya, Tanzania and Mozambique to Madagascar, the Comoros, Mayotte, Mauritius, Réunion and the Seychelles.

Like other corals in the southwestern Indian Ocean, it faces threats from global warming, rising sea temperatures and the increasing occurrence of severe weather conditions.

Ocean acidification affects corals as does increased siltation from human developments and mechanical damage to reefs from fishing activities.