Lol - comparing an opaline with a dwarf doesn't realy work
However, the idea that your problem may be crowding could be correct. While you are not over-stocked per say, you do have quite a few active fish in the tank. Also, the dwarf, seeing as you've only had him a short while, will have only just settled in.
Take him out of the net - this is extremely stressful and, dwarfs being particularly prone to disease, may ultimately kill him.
Add some floating plants to your tank. That'll give him a specific part of the tank to defend and may help reduce aggression. Besides that, add plenty of other hiding places, re-arange the tank a bit and then give it time. Dwarf gouramies are not usualy too bad with other species of fish and he should eventualy calm down. As long as he isn't causing any physical damage, there's hope he'll come round.
If you see no improvement over the next couple of weeks or notice things are getting worse, return the dwarf to your LFS and replace him with a male honey gourami instead (may or may not prove better). Alternatively, male banded gouramies (colisa fasciata) grow larger, but are more amiable IMO. Again, there's no guarantee. You could try a female pearl as a last resort - I say last resort because female pearls enjoy company but you don't have room for more than one.
