I have a fourteen-year-old Upside-down Cat. He has lived in three different houses over the years - I know how old he is by when we moved out of the rental we were in when I got him.
My oldest so far has been a 3-spot gourami that lived to be over 7 years old. My current oldest is the TT eel in my avi, but I'm not sure exactly how old he is since he was already about 4" long when I got him 2.5 years ago (there's a good probablity that he was a bit stunted at the time since he'd probably lived most of his life in a crowded 10g).
I have a 10 year old Syno. nigrita that was lucky to survive a savage beating by some cichlids when he was under a year old to grow up into a nice fish
10-11 year old common goldfish I won at the state fair, not sure how much longer it's got, has a tumor the size of a dime on its side, that has to shorten his life expentancy.
A seng bichir that is extremely stunted I bought him 4 years ago and he was 6 inches and he is still 6 inches. Guessing he was a trade in so I have no clue how old he is. He was in a 135 and all the other fish outgrew him now he has his own 55. Very bummed as he is my wifes fish and she is very attached to him. Then I have a 2 year old livingstonii and 1 year old paratilapia polleni
Ive got a black shark that is close to nine years old.
Not sure how hes lived so long, the first 4 years of his life he probably had 3 water changes (stupid noob fish keeper), he still managed to grow from 2 to 12" though.