If I had that tank, first I'll change the subtrate as I can't stand bright gravel LOL.
Mabey some river sand.
And then just have a few tall plants but nothing too bushy because there isn't much room anyway.
Also, some kind of cave for your female opaline gourami to hide in.
My camera isn't working at the moment so thats why I had to describe mine. :lol:
(The only thing I don't have is a cave because I don't have any fish that need priversy).