Cnidaria; Corals and More

Cnidaria is a phylum that includes much of the non-moving marine life admired at Koh Phangan dive sites. Corals soft and hard, sea anemones, sea pens, hydroids (and sea jellys too?).

Now there’s an excellent reference to all these creatures in the Indo-Pacific Corals guide book.

A big range including the Hard Corals, Anemones, Corallimorpharians and Zoanthids. They all have tentacles in multiples of six. (4 Albums, 1 Gallery)

Also known as Alcyonaria, they include Soft, Whip and Fan Corals, plus the Sea Pens. Their corallum has eight tentacles (not in multiples) and their tentacles are feathery, not smooth. (3 Albums, 3 Galleries)

Cerianthids are solitary tube dwellers, differing from real sea anemones by having extra tentacles around the mouth, as well as living in a tube. They live mostly buried in the sand and when disturbed they quickly retract.

Divers and snorkellers beware; these delicate structures pack an unpleasant sting. Of course it is also best for our marine life as well as your own comfort not to touch anything! (4 Galleries)

Beautiful photo subjects for divers and snorkellers but keep clear if they have tentacles. Something special to see in Koh Phangan waters. (6 Galleries)

The comb jellys are actually in a different phylum from the cnidarians, but we have put them here to keep the gallery structure simple!

Thankfully they are not commonly encountered when we're diving around Koh Phangan, so we don't have many images.