Phyllodesmium kabiranum by Todd Garthwaite

Dear Todd,
This is an interesting find. Most species of Phyllodesmium feed on soft corals and in association with this diet have evolved some unique features. If you have a look at the other species on the Forum you will see this fedding habit has allowed a whole radiation of shapes and sizes in their evolution.

The two most interesting points is that the nematocyst stinging cells in soft-corals are too small to be of much use in the nudibranch defence so they don't have the usual aeolid cnidosac at the tip of each ceras. Instead they can readily autotomise [break off] their cerata which produce a sticky secretion to confuse potential predators. Their other claim to fame is stealing microscopic plants called zooxanthellae from the soft corals they are feeding on. They keep these alive in their tissues where they produce nutrients for the slugs. [see the pages on Solar Powered Sea Slugs].

To your question about the soft coral your animal is feeding on. Firstly this is probably the first observation of it feeding on a soft coral so thanks very much. As to the identity of the soft coral I am not sure It looks like a Xenia or close relative, aand hopefully someone will be able to identify it for us. If you have a photo showing more of the soft coral colony it might be useful in getting it identified.
Best wishes,
Bill Rudman