Cleaner wrasse are very odd fish. I got one a year ago, only 2 weeks after my tank was set up. It quickly became my favourite. It would clean the fish, and even clean my arm if I put it in there, although it occaisionally caused me to jump while doing maintanence - he would rip out my arm hair! It hurt!
He was very hardy, and readily ate frozen foods, he especially loved brine shrimp. He ate parasites off of other fish too.
However, he brought his own death (and all but one of the other fish's) in with him. When I got him, he had a light infection of ich. However, he (or I should say "she", all wrasses are female until breeding time) fed very well, and soon expelled the parasites. However, the ichthyspirithius still lurked in the tank at low levels, and when I introduced a "Black Percula" Clown fish, he became infected.
Thus, a chain began. The wrasse was the last to die, and the only survivor was my Green Chromis/Golden Damsel hybrid.
Then, 6 months later, I got another one. She found a nice "bolthole", and remained there, not emerging to eat. Oddly enough, she did in fact eat frozen foods the first day I brought her in. And she wasn't stuck; I placed my fingers near her hiding place one day, and she swam out of the hole - then back in. She starved to death.
-Lynden