Beginning more than 100 million years ago (during the Cretaceous), Helioporid corals were widespread on Earth. The only remaining, living species (blue coral) in the genus Heliopora occurs in parts of the Pacific Ocean. Iron salts in its skeleton produce a bright blue color, and it is frequently exploited for its beauty. Live blue corals are harvested for the aquarium industry, and blue coral skeletons are used to make jewelry or trinkets. Their tendency to live in shallow water has made blue corals vulnerable to other impacts from humans such as damage from fishing and pollution. CITES (Convention on International Trade in Endangered Species) lists blue corals in Appendix II, which means that their trade is regulated to keep them from becoming endangered. Export permits are required to take blue corals from one country to another, and are issued only if authorities determine that the export will not be harmful to the species.

Anthozoans (anemones and corals) have stem-like bodies that anchor to the ocean body or other surface. Tentacles radiate like petals around the top of the stem (anthozoa flower animals). Both their bodies and tentacles are hollow, opening into a mouth in the center of the flower. Anemones and corals capture food with their tentacles and push it into their mouths. While they mostly eat small, floating food (plankton), stingers (nematocytes) on their tentacles allow some anthozoans to consume larger prey (even fish or crabs) by stunning them first. Food travels from the mouth to the hollow space inside their bodies, where it is digested. Since they have only one opening, waste products are expelled back out their mouths. Some anthozoans benefit from a relationship with unicellular algae (mutualism). While the coral provides a safe place for the algae to live, the algae makes food by photosynthesizing.