My female purple sea slug built her nest after 2 weeks I got a pair in the tank. I saw they mating couple time. They were healthy and colorful with phytoplankton. My pair seemed didn't bother any of my coral. They are beautiful in the tank but you need to have set up your power heads or the suction tubes in your tank because they will let themselves to float around to find new spots. And that's what happened to my pair; both were sucked into the power head. Hope her egg nest will hatch.