Third poly is also a Senegal and is my youngest. She was a rescue because she had a crooked a spine. She's perfect now, and almost as big as the albino. He is 7" and I've had him almost 6 months. He's a piggy. Here's the family photo:View attachment 1362834
They are precious. Sorry you are having problems with aggression. As long as the albino isn’t constantly antagonizing the del on a daily basis, maybe see if it settles down.
Another option is getting a bigger bichir than the albino and seeing if that keeps him in check. Or 2 bigger bichirs. heh. Then you could let the 2 bigger bichirs re-establish the tank as there own....this would require separating the albino into a different tank for like a month. Don't know if this will work necessarily, but did work with my moke who killed all my dithers and was terrorizing my other polys. Now everybody gets along for the most part, aside from the occasional shredded pec fin, finlet, or tail.