My larger fish allow the cleaner to "come aboard", but I have found the smaller fish stay clear. I have a sailfin tang, hippo tang, scribbled rabbitfish, heniochus butterfly, and even the lawnmower blenny that allows the cleaner shrimp to clean them. The neons, diamond goby, cinnamon clown, and the coral beauty stay clear. I put the shrimp in the tank just about 1 month ago, and it took the fish maybe 2 wks to feel comfortable for this to happen. I have 2 fire shrimp that have never really cleaned anyone...they have been in the tank over a year. He definately has been worth the money, even thinking about getting another, the poor guy is really busy all day!! The fish stand in line for attention.