More than likley Altifron or Altifron sub-species as Japes has said. The head shape is the key thing i use to differentiate the species; Altifron have a much steeper-inclinded face and taller body compared to the Dicrozoster/Surinamensis varients, not to mention the Pre-operculur mark;
isn't the more appropriate reaction? Wrong picture for "Satanoperca jurupari" as well.
To the OP: if the lateral spot is 2 scales wide x 2 scales tall or smaller (which seems to be the case to me), you definitely have a G. altifrons. Even if it's slightly larger, it still looks like a G. altifrons variant.