In the average reef tank only very low stocking levels of fish can be used. A cleaner wrasse takes up 10 cm of fish 'space', unless you have a reef sized system(!) it's a waste of space and the wrasse will die slowly, and probably painfully, from malnutrition. Get a cleaner shrimp instead. It does not impact on a wild reef in the same way (think of all the poor wild fish who have no-one to clean them), nor does it take up precious fish bioload. There are also large numbers of fish which, especially as juveniles, will clean other fish. Cleaner wrasses should not be kept!
My first cleaner wrasse lived 27 months. It died while I was away for two weeks for work and the tank was being cared for by my brother. It had jumped out of the tank. It was while the covers were moved aside during feeding or it made it through one the few small gaps that are near the filter tubes. When I got back I could not see my favorite fish at feeding time and I looked all around the tank only to find it dried out remains. When it wasn't cleaning the other fish of topical parasites it seemed to be eating the frozen mysis and brine shrimp that I fed the other tank fish.
I kept a cleaner wrasse in my FOWLR 1100 L tank for over five years. He only recently died because I had a bad outbreak of Velvet followed by an unknown bacterial problem. This killed all of my fish except a HuMu HuMu. If not for the bacterial outbreak, who knows how much longer my cleaner wrasse would have lived for? He had about 15 medium-large fish to constantly clean, but he also ate frozen foods like formula 2 and Mysis. He was very plump and happy. Prior to this cleaner wrasse I had another one that lived for about 2 years. Unfortunately he was gobbled up by a hungry sweetlip.
Cleaner wrasses are able to be kept in Aquariums of 350 L or larger, providing that they have a large tang or angel to feed upon the tiny parasites that are not necessarily visible to us. With time, I have found that they will soon readily feed upon frozen food such as baby mysis shrimp. We as aquarists must depend upon proper collection of all species of fish and invertebrates and know their needs as well. Water quality of an aquarium is the most important part.
I'd like to quickly share my experience with the Cleaner Wrasse. Mine was given to me by a friend who was starting a new tank that never saw the light of day. This is this fishes 4th tank! It has been kept in a reef tank for 6 years already and does extremely well in my tank. Maybe due to the fact that it eats very well. It takes brine, cyclopeze, and nori. It also tries to muscle down mysis if it can find a small piece. So far I have not had any problems with this fish and don't forsee any in the future.
I thought I would share a piece of information I have discovered about cleaner wrasses in the home aquarium that I haven't seen posted anywhere else. A cleaner wrasse was the second fish that I purchased, before I had done any research in to their care and controversy. I think part of the reason that people have such low success rates with these animals is their small and highly specialized mouths. The specimen that I have now had for 7 months seemed very interested in the food going in to the tank, but after watching him carefully I realized that he would only even attempt to eat the smallest chunks of mysis shrimp, and then most would get spit out, or the investigation would be aborted altogether. I discovered that by shaving the mysis shrimp off the still frozen block with scissors before thawing, there would be enough very small pieces of mysis shrimp of the right shape to be ingested by the wrasse without problem. He does seem to need a special size, shape and orientation to the food piece before he can eat it, but I believe that it was this method that allowed him the time (without starving) to learn to eat the other types of prepared foods that are fed to the tank, such as baby brine shrimp and now algae flakes and surprisingly, bits of the brown and red algae sheets I put in for my tang. I would still not recommend buying one of these guys, but if you do, training it on prepared foods this way might at least give it the best fighting chance. I've also discovered that it's partial to any frozen food that is white, such as finely shaved pieces of scallop which it attacks with vigour, but again the size and shape need to be right to fit in its parasitivore adapted mouth and throat.
These pages have enough comments to give the reader a basic idea on the topic. Further comments are still very welcome (through the site's contact form) as long as they provide new and/or advanced information not yet discussed in the existing ones.