What is the difference between hard coral and soft coral?

Corals are marine (saltwater) invertebrate animals that usually form colonies of individual polyps, mainly in tropical reefs. 

Hard coral is also called stony coral.

Hard coral is in the sub-class Hexacorallia (hexa means six), whereas bue coral and soft coral are in the sub-class Octocorallia (octo means eight).

Hard coral is in the Scleractinia order, whereas soft coral is in the Alyconacea order.

Both hard coral and soft coral have individual polyps.

Hard coral has polyps with 6-fold symmetry most of them with each polyp having six tentacles, whereas soft coral has polyps with 8-fold symmetry with each polyp having eight tentacles.

Hard coral has cylindrical tentacles and taper to a point, whereas soft coral has pinnate tentacles known as pinnules (stubs or paddle-like).

Hard coral has a rigid, hard, calcium carbonate skeleton to protects its soft body, whereas soft coral has flexible, minute, spiny skeletal elements called sclerites.

Both hard coral and soft coral are found in all the world’s oceans, especially in the tropics and sub-tropics.

Hard coral includes Brain Coral, Staghorn Coral, and Plate Coral, whereas soft coral includes Tree Coral, Sea Fan, and Sea Whip.

Photographer: Martina Nicolls

Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM