Quoting SG_Eurystomus below:
> How big is that [Zambian petricola] , and is it a single; or do you have a few?
About 8 cm SL. I have two. I have the opportunity to get some more, but a certain friend of mine

has told me I have too many fish in my tank, so I think I'll have to resist this temptation!
> And the giants I've seen were quite a bit lighter in color; and had a wider mouth; like that
> Zambian has. It might be the tank in wich they were; but they had less spots and the white
> parts were more prominent. Maybe there are a few "Giants" not just one....
Could be. Erwin Schraml, a good friend who knows his fish, thinks this fish looks more like S. tanganaicae. IMO, I also have S. tanganaicae and it looks different from the fish I captioned as S. petricola "giant". There is a similarity, though.
> How big is that "Giant" petricola?
10-11 cm SL
>
> That Burundi matches perfectly with what I know as such.
>
> Those are pics of your own fish?
The top two of the "dwarf" petris are not my pix (though I have dwarf petris also), and the second picture of the "real" Burundi petricola is not my fish. All others are.
I also have an unusual Zambian petri with a very copper color and a very rounded head. It rarely hangs out in the open, so is hard to photograph. Another 3-4 fishes that look rather like petris in body shape but have coloring more similar to S. polli. They each look different, I don't think they are the same race/species.
This is one of the fish on the petri-polli interface:
Different from my "real" polli, but also different from my other petris.
The other pictures I'll post when I can get good pix of these fish without having to tear the tank down.
Dinyar