They can survive without a cleaner wrasse but I have to say that keeping them with a cleaner wrasse is a plus. Any time I notice my regal tang getting any spots,its gone right away and also it should help you from spending on medication! My cleaner wrasse's check everybody on their community constantly. And are not pest like most wrasse's are. I had two in my 55g with my Regal Tang. But moved it with 1 cleaner wrasse into my 180g. Weird thing was both cleaners got along in the 55g but not in the 180g so I have one in the 55g still for backup! Don't forget Cleaner Wrasse's are hit or miss. My luck has been good with them. Mine eat alot and are growing healthy and I had mine for months now. From experience I notice, that if they past the 1 week or two week period than your more than likely to have a keeper cleaner wrasse! I've went through a couple through the last 4/5 years lost a couple that where shy and stayed in a rock till it died or just stupidly got stuck under a rock over night to let the hermits eat em. The one in my 180 gal sleeps somewhere's I havent figure out yet in my heater lol. Great fish. Good luck if you grab one.plus their cheap..Im in Canada and I buy them for 15$. Also Blood Shrimp Are Good Cleaners well, I have a pair of those as well. My Lyretail Anthias Love's getting here daily cleaning,as she sits in their station at least one a day. Like a check up or something!