I've only been in the hobby for a little over a year, so the one I've had the longest is my Figure 8 puffer at 1 year. He's probably closer to 2 or 3 based on his size when I got him. He's still alive and kicking.
Betta Splendens - 5 years. He was a simple blue veil tail. Lived a long full life, multiple moves. Started out in a 5 gallon vase 2 years, 55 gal aquarium for 3 years.