Male giamt gourami

[Charney]

does anyone have an idea of when male giant gouramis start developing their head bump? I have one that is probably about a year old and 16 inches or so. I cant use his dorsal fin because it gets slightly chewed. I am considering getting a golden giant gourami but dont want to end up with two males

 

[thebiggerthebetter]

I usually don't pay attention to sexing of my fish, so take what I say with a pound of salt but if memory serves, our GG males start to be more or less obvious due to the forehead hump by about 1.5'.

If one truly pays attention, perhaps at 1' it is doable but this is a speculation.

Can't say I can report a difference in the species (because again I don't pay attention enough), although we have three of the four - 3 osphronemus (one grey, two pink), 4 redtail, 2 exodons.