I've barely been in the hobby 3 years, so no records here, but a few of my fish have been around for a while. My maroons are probably around 4 years old -- I'm their fourth home AFAIK, and they've both lost the bottoms of their stripes (someone in the clown/nem forum mentioned this happens as GSMs age). I think I've had them for a year or so. My ocellaris is at least four or five; I've had her for a little under two years and a friend of mine had her for several before that.
The animal I've had the longest is actually my tiger pistol shrimp. As soon as my first tank was done cycling, I bought the critter that made me want a SW tank in the first place -- Digger's been with us almost three years, with no signs of stopping. He's on his third goby now; we lost the last one to a surfing incident.