[Puffer Pita]

IME and research, dwarf gourami will ONLY mate and spawn in a separate tank on their own, no water movement at all, no filter, and live plants. He will build an extensive nest with bubbles and pieces of plants, then when its ready and she's willing, they'll dance, he'll turn her upside down, and while upside-down, she'll lay the eggs and he'll fert them. Then he'll put another layer of bubbles and plants under them. The female will then need to be removed, as he will become very aggressive towards her, and once the eggs start to hatch, he'll need to be removed or he'll eat them.

I recently had mine do this. It took several weeks and was fascinating to watch.

If they are not given a place to spawn, she'll either drop the unfertilized eggs or her body will reabsorb them.