Hydroids; Hydrozoa

Watch out for Hydroids! When diving or snorkelling you must beware of these delicate structures, as they pack an unpleasant sting. They are in fact colonial animals and can be encountered at most of our local dive sites.
Then again it’s best for Koh Phangan marine life, as well as your own comfort, not to touch anything at all underwater!

There is a possibility that some of these photos are actually of black corals - it's not easy to be sure.

They are all equipped with a battery of stinging cells.

Beautiful, small, delicate structures. Technically they are classed as fouling organisms.

Delicate, feather-like structures that are poisonous to touch.