Herichthys minckleyi come from isolated lagoons in north Central Mexico, called Cuatro Cienega's that are in the middle of the desert. There are a number of endemic species there found no where else, including a species of turtle, and a sunfish.
Your photo does resemble a minckleyi, but the idea of someone letting such a rare species go (to me) is crazy.
Almost all cichlids of tribe Heroini can possibly interbreed, and this includes cichlids from as far south as Uruguay and to Texas in the north. There may be as many as 100 or even more species in the tribe, so trying to guess a combination from that lot, is a bit like finding the needle in a haystack. Especially if the person trying is unfamiliar with a majority of them.