Technically they're not geophagus, they belong to the genus Acarichthys, not Geophagus.
They are closely related [thus sometimes being called threadfin earth eaters], and maybe once were lumped under the genus Geophagus?
They look kinda like a surinamensis when young and badly photographed, but are quite different. They have a black and white patch on the top of their dorsal fin, the anal and pectoral fins are orange, and they have a black bar running thru their eye, which seems to disappear when they get older.
If you have a look at some adult pics you can see how different they are.
http://www.amazonasrochen.ch/pictures/a ... 010011.JPG
http://www.amazonasrochen.ch/pictures/b ... 010025.JPG
http://www.acara.be/mambophil/cpg132/al ... elii01.jpg
http://www.wallpaperfishtalk.com/wallpa ... 000040.jpg
http://213.180.95.58/artregister/artbil ... hansen.jpg
The first two pics are from this page that I randomly found while looking for pics. Takes a while to load, but well worth a look, an amazing collection of amazon fish!!