What is the life span for a Beta fish?: "Given the deplorable conditions that Bettas are kept in many of the chain stores
I think you're probably very lucky to have him survive that long. That's a whole other issue though that I won;t get into.
I personally have had male Bettas live over 5 years with excellant care and I've heard of 10 but that must be very exceptional But they should do well for over 3."