It’s hard to help when you don’t or won’t listen to others opinions. I’m saying that a few people think it is the pleco, but don’t believe everything. Do more research on the Bristlenose Pleco behaviors and feeding, because it seems like you are taking our information and advice blindly. That’s great that you are experimenting by taking the pleco out, but you have to understand that evidence-based (not saying
@wasmewasntit is wrong) information is the best information. Majority vote goes to the Angels, which, as you said in post #52 is just adding to the evidence. “I've watched them escape each other”. You would infer that they have been aggressive to each other. It is a heavy coincidence that the dominant male in the social structure had no wounds. You are next to the tank probably 2% of the day, and just because your fish get along then doesn’t mean they don’t fight.
My fish (I have 4 bichirs) are territorial. They broke the spaces of the tank up into territories…but the heirarchy fish, a 14” Palmas, kept wanting to take over the other, smaller bichir, territories. Bichirs will not fight back to a fish larger than them, so their instinct is flight. However, I was never there to see it. Every time I would enter the room, they would all stop for 10 minutes or so. It wasn’t until I sat there for 30 minutes or so when I realized that the broken finlets on the smaller ones back weren’t caused by him getting stuck some where, but the largest one attacking, or showing everyone who’s boss. The cichlid social structure is similar to that of humans. There are popular (dominant) males or females, and then everybody in between. Maybe a few rowdy ones want to challenge the ruler, then they get put in their place, or the ruler gets put in his place.
It is most likely not HITH because it has not spread to other fish in the tank.