Including an Asteronotus, an Atagema, a Discodorid, a Hoplodorid and a Jorunna; some that you will never notice and one that you can see on nearly every scuba diving and snorkelling trip around Koh Phangan.
Named after it's apparent similarity to the opening of a cesspit - how nice!
Not easy to photograph due to its dark, sponge-like appearance. Also known as Atagema or Trippa intecta.
This nudibranch doesn't swim so much as rippling its body and gliding over the bottom like a hovercraft.
It is not easy to be sure if we have the correct name for this Hoplodorid, as at least 2 other species look very similar.
This is the nudibranch that most divers can spot on many of the dive sites around here. They can grow to a large size and feed on the blue sponge, Haliclona species.