The coral reefs of the Republic of Fiji are known as the soft coral capitol of the world. Corals can be divided into two primary groups, known as hard corals, and soft corals. The hard corals are the reef builders that lay down a skeleton of limestone that over time becomes the hard structure of the reef itself.
Soft corals, on the other hand, lack the hard skeletal structure of their hard brethren. Instead, they have disconnected spiny filaments that give them some degree of support, and result in a spiky, grainy texture to their flesh.
Soft and hard corals are also differentiated by the number of tentacles that each polyp bears. Hard coral polyps always have six tentacles, while soft coral polyps always have eight.
Today’s photo clearly shows the arrangement of eight tentacles around the central mouth of the polyps extend out of the basal disk of this soft coral. Beyond knowing that this is a soft coral because of the tentacles, I am at a loss to provide further identification. While I am a marine ecologist, I specialize in temperate, rather than tropical ecosystems. In trying to identify this species that I saw in Fiji, I was quite surprised to discover that there seems to be a real lack of identification materials for corals, hard or soft, out there.
I saw this coral while on vacation in the Republic of Fiji in April 2015. We were diving at a site called Coral Garden off the island of Taveuni, the third largest of the islands of the archipelago.
This photo was taken with a Canon EF100 mm f/2.8 macro lens on a Canon EOS 5D Mk. III in and Ikelite underwater housing. Light was provided by two Ikelite DS-161 strobes in eTTL exposure mode. The exposure was set to 1/200 sec. at f/11 and ISO 1600.