Hi Peter,
I can't sex the fish from the pictures and probably couldn't in person without others of similar age to compare it to.
About the I.D., did it come in with the Geophagus "tapajós orange head"? It is not an altifrons and does not have the tail pattern of G. "tapajós II" so it doesn't seem to be from there. I don't think you can make a confident I.D. without knowing where it is from, but it does share many traits of G. abalios. The "paired" bar that runs through the abdominal spot, and the paired anterior bar and three posterior (single) bars, red eyes, tail pattern, straight head profile, and lateral blue and yellow striping are all characteristics of that species. The only obvious dilemma would be how they came in on the same shipment as fish from the Rio Tapajós (being from Venezuela: Rio Orinoco, Rio Cinaruco).
Much younger fish (3") but you can compare to these juvenile Geophagus abalios
Ed