I have a nero 5 on the other side and I've watched them pretty extensively they don't seem to be fighting at all. Unfortunately I just don't think there is too much I can do for them other than trying the brine shrimp which I ordered. I can do a water change but the water quality I tested is near perfect in terms of ammonia, nitrates, nitrites.I’m starting to question if it’s an issue from mixing them with damsels, always read that it wasn’t suggested. Damsels can be aggressive and territorial, especially if they are bigger than the clowns. Might be worth putting a cheap power head or wave pump on that other side to see if it’s lack of oxygen. It can’t hurt to try, Petco carries the koralia nanos, $50 isn’t a major gamble.