Sorry. An F1 is a first generation hybrid. In this case the result of a cross between a BG and a GSF. If two F1's breed, they will create an F2. If two F2's....you get the picture.
It is generally acknowledged that the F1 fish hold the most desirable characteristics of the cross, and that each succeeding generation will possess fewer positive qualities, and more negative qualities. Generally acknowledged...more research is needed where HBG are concerned, in my opinion, in order to determine where in the lineage such degradation might occur.
The fish in the photos display the attributes I would consider desirable for HBG, and that along with their size is why I think they are F1's.
