The LFS estimated about two years or more. He was actually donated from a tank breakdown. The previous owner must have taken great care of his/her fish. I would have loved to see their other fish. I got a great deal on this guy, especially taking into account that they aren't seen in the trade too often.
Here is a picture I took tonight. I caught them during their sleepy time. hehehe they were so out of it. Two of them kept banging into the others since they sleep so close together. I think I surprised the first one.