Off the top, welcome to TFF.
This species, which is Trichopodus trichopterus, is one of the more aggressive of the small/medium sized gourami species. You have a large tank which is good, as males and females of this species have been known to tear into one another until the strongest is left alive, and then sometimes go after other species. Males being territorial are worse than females, but the latter are not exempt from this behaviour.
Discerning male/female is not always easy especially in young immature fish. The more pointed dorsal and anal fin of males can be hard to discern.
You have an issue looming with the BA tetra. Being a shoaling fish, they need at least six, preferably a few more than that, to be at their best and free of additional stress. It is likely they will decide at some point to tear into the fins of the gourami; this is a normal proven reaction of shoaling fish when the group is too small. Of course, the gourami may beat them to it and go after them first.
Byron.