hey i have one of those in my tank! it hitched a ride on a zoo frag or something and ive been trying to figure out what the hell it is ever since. Unfortunately i cant get a picture becuase it only makes itself visible at night and any attempt at getting a good shot fails, just a little bigger than a quarter, hes only slightly fuzzy, but dark blue/violet and has some white dots on him, bright red eyes, and definitly a filter feeder, its pretty cool watching him feed, he kinda waddles out and maybe sifts through some detritus and then sticks out his filter feeding arms. Have not noticed any aggressiveness at all towards corals except he did knock over a ricordia frag one night, that was an akward/confused morning....
