Cleaner wrasse extend life of other fish?

[foxfishfan]

I have had my 2nd copperband butterfly alive and healthy for 9 months, which is 6 months longer than the 1st. I notice the wrasse cleans the other the tangs and copperband when he isn't cleaning the porcupine puffer which is half of day. Cleaner shrimp were good but usually ended up as dinner and were in the tank when my 1st copperband died after only 3 months. I know how fragile these guys are and am amazed this guy is healthy and somewhat fat after 9 months. Based on my experience, cleaner wrasses are almost a must in a tank with predominately fish and are well worth the few dollars they cost.