Here's another one: some guys actually raise them. And when I say that, I mean they constantly feed them, until the fish reaches a considerable size.
After which, the person(s) in question claim to have caught them from some lake. And the rest is history.

It isn't hard to raise fish, given the right environement. Especially a warmwater species.
I personally don't know of such people, but it has happened and will continue to do so, as long as some are in cosntant search of public attention.