I have a small tiny redish orange one on one of my live rocks and many little purple ones that have come in as hitch hikers never actually bought one but have seen bright yellow ones too.
seen a black with white strips on one at a lps that looked cool when they took it out for customer 5 mins later the said oops that guy just bought a tube the crown was in the back off tank wide open and they didn't really acted like they cared for the other guy lady was rough getting it out for that guy
why would I want something that takes nutrients out of my water. My corals need nutrients damnit! So you are saying all it does is crap and eat all the good stuff? Sounds like children!