Octocorals

As I mentioned in my last post about Stony Corals, I want to be able to identify coral by their groupings in order to make it easier to remember it’s specific features and look it up later on. This section is all about octocorals (aka Gorgonians).

You can read about this project in the post “A Fish Journal for a six-year-old” and you can see all the posts for this project using the tag “Fish Coloring Book“.

Octocorals get their name from the eight (Octo means eight) tentacles surrounding the mouths of their polyps. This group of corals are commonly referred to by their subclass name; Gorgonians.
They also often get confused with soft coral. This is likely because most Gorgonians have a flexible structure that bends and waves in the water currents giving them the appearance of being soft.
Although Gorgonians don’t have the hard, rigid skeletal structure of stony coral, they are very different from soft coral in several ways.

Gorgonians have a central skeleton made up of either tightly bound or fused calcareous spicules (cal-KARE-ee-us SPIK-yools) that create a firm but flexible structure. Examples of gorgonians include Sea Whips, Sea Rods, Sea Fans, and Sea Feather Plumes – all these names reflect the shape and flexibility of this group of coral.
The core of the gorgonian structure is surrounded by a gelatinous material called the rind and all the coral polyps are embedded in the rind. Most gorgonians are attached to the substrate (surface or bottom) by a single stalk called a holdfast. The holdfast secures the colonies and supports the main branch from which many smaller branches grow creating different patterns and shapes depending on the species.