SA Bumblebee Catfish Life Span?

I have 3 of these fish and I keep reading that they live 3-5 years, but I have 2 that are 6-7 years old. What's the more common life span of these small catfish?

The 2 catfish are now 8 years old. They were full grown when I bought them when I started high school. I also have 3 more, one is still a baby and 2 are 1-3 years. No matter where I read it states they only live 2-5 years or one site states 2-3 years. It gets confusing. Catfish along are and can be a very hardy fish. The two old ones survived freezing temps during Superstorm Sandy and the following blizzard, along with multiple tank changes and so on. The hardiest fish I've kept, besides the Black Neons I keep as well, which for some reason survive everything as well. While everything else dies, they keep going. Had both species survive both ick and fungal outbreaks. haven't had any outbreaks the past few years now, besides the one time a petsmart worker took an angel out of bag with her bare hand and transfer it to another bag, in which killed off my other two angels, including the one she handled. Nothing else died besides the angels.

For me I love catfish. I would do a catfish only tank, but I wouldn't see any of them.