I had one. I read somewhere that they only live for two years, but that is what I read only. They also are kind of aggressive. Mine bit out the eyes of two different flagtail's that I had in the tank. Not a good tankmate for slow moving fish in my experience.
i would only get one they are very conspecificly aggressive and are also said to hate and silvery fish other wise they aren't usually to aggressive and make a good top water fish for an oddball or cichlid tank
As for there life span it is rummored that specimens over 5 years of age are rare in captivity but i haven't seen any credibly information on this
I have 2 living with a silver aro and polys, had no probs with them with aggression.
They are a very skittish and nervous fish, they go mad and bump into everything when I do water changes.