Firstly, are you absolutely certain they are both female? Second, how big are they? Lastly, if they are both female, considering they were only just introduced to the tank, the behaviour you are seeing should just be to settle hierarchy and should eventualy settle down as the fish assert their dominance/decide positions etc. If this has not stopped after about a week or if you see signs of serious physical damage (anything more than a couple of scales having come off or a little nip at the end of a fin), I would consider either taking both females back (and replacing them if you like with two different females - consider getting two females that are each a different color morph of the three-spot gourami. Opaline is one color morph but you already have the opaline male so consider getting a female that is gold/blue/cosby/lavender/platinum or whatever and another female of the same species but a different color morph - so you'll end up with the 3 three-spot gouramies but each a different color. This will also help keep aggression to a minnimum.) or adding a couple more females (slightly larger size if possible) to even out the aggression. The second method is more likely to work but requires that you have a big tank (at least 55 gallons) as you'll then have 5 opaline gouramies in there.
