Sorry for your loss Jim. They don't die of old age that's for sure. I know of bichers imported in the mid to late 90s that are still alive and well to this day.
Idk the exact life span but iv heard of some being 20+ years old and have read something years back on the internet of documentation of some in the wil being 50 years old .... Idk if that was true or not that's just what I read
I have an Endli that was imported in 1996. Only about 19" long but really wide head I have only had him about 2 years. He came from Jurassic Aquatic when he was shutting down the business. He was one of Mikes personal fish. I guess what I am saying is they can live a long time.