very nice smallfry..it is always nice to see someone quick on the uptake! Your ratios are good!
Eoin, your post prolly got buried and missed.
And as mentioned..it is NOT a good idea at all.
And haven't you already had a gourami problem recently?
Perhaps if you have a 55 or larger, you could have a blue gourami and a powder blue or a powder blue and a flame.
More space allows more exceptions in most situations regarding our finned friends.
Even bettas do not fight to the death in the wild...they rarely fight at all (though its ugly when they do..that is what brought them to bettors attentions in the first place)
My grandfather had several males in a huge shallow pondlike tank. No major damage to any. But who has a 6ft tank that they think to put two bettas in? Or one 3ft so planted the fish are invisible?
basically here is the easier rule of thumb: there are two species that are more betta like in temperment.. the dwarf gourami (Colisa)...and the two spot (Trichogaster t.) it's summatran sub sp. the blue gourami. Any mix with these fish in species groups or communities, has to be carefully planned.
And a dwarf gourami male is just territorial period, if he is setting up a nest , he is just as likely to shred or maim an uninvited femaleas a lesser male. the larger fish are in general calmer in temperment.
liquorice are tiny, gentle, social cave nesters from soft moving waters. Discounting the fact they need specialized water requirements (which other gourami wil enjoy but not reversible); the larger and aggressive gourami may stress them to death or outright stalk them and kill them.They are also sensitive like neon tetras and mostly use the gills proper. Chocolates also are special needs and are sensetive to harrassment. Even if there is an unusual aggressive amongst them.
Ulnless you carefully research the species for the most part: Don't Mix Labyrinths.
And unfortuneately the most congenial are the mouthbrooders or the 8-10 inch ones
And if I remember..you already have a pretty full and small community.