Those little white flowers at the base are the egg ribbons containing 1000s of eggs. They are so slimy I had to use a paper towel to get them off using a separate container and rinsing the rock with fresh salt water. I placed the Duncans into the QT tank as I saw movement from within one of the polyps before I realised there were nudibranchs in the tank.
Before anyone comments, I am sure the nudibranch is more deadly for my fish and corals than the paper towel fibres which may have microscopically remained, but it was the best I could manage under the circumstances. They were also at the back of a rock so now I am expecting more in the tank. I am seriously not having a good run with marine as a choice
Has anyone else come across this problem and knows how to eradicate them? I will keep googling in the meantime.