I bought my cleaner wrasse when my fish came down with a case of ich.
I was told put one on the tank and I would have no problems with ich (some LFS are scandalous). I also bought my UV steralizer at the same time. I was also told when I was in Hawaii that it was good to have one by a fish store there too (no, I do not want to buy any lake side property in Florida :lol ).
At the time I only thought it was bad to buy the Hawaiian Cleaner Wrasse as those do not adapt at all to eating prepared foods.
Vitamin B6 is an appetite stimulant, I don't know how it works but it does. It worked on me when I was a kid with mono ^_^
Plenums and ultra deep sand beds > all other setups!