I've seen some discussion on that fish. It's clear it is not margaritiferus (as has already been said, that fish is likely either extinct or not definitively identified), but that name has recently been stuck on a fish that some consider a race or distinct species related to robertsoni, alfari, etc.
That's definitely an interesting fish to keep based on the uncertainty of its status (and its great looks!). There is a similar discussion on cichlidae.com with a couple of collection photos......but, unfortunately, no definitive answer as to its identification.