Possible fin rot


something smells fishy
So I'm at work so I haven't seen the fish yet, but trying to get a jump on it. I have a empoeror angel (2") since beginning of january with no issues. I just got a heniochus butterfly about 2 weeks ago and he didn't like him at all, and since them I have added 60lbs. Of rock and reaquascaped the tank to try to curb aggression. he has started to leave him alone but still goes after him every so often.

wife noticed this morning that his Fin looks white and is jagged. like I have said I am at work and have not seen him yet but judging from what I have read it is fin rot. I've been feeding the tank PE my sis shrimp soaked in garlic to try to help immune. also bought algae sheets for the angel and tang. all the fish in the tank are eating good.

I read that if they're eating good let it ride to take its course and do a good size water change. is there anything else that I should do.

is the my sis shrimp a good source of food or should I be supplementing it with some other frozen food as well?

when I get home I might be able to give more description of the fishes issue. I'm thinking he got a little stressed out when I put the butterfly in the tank but he seems to be more accepting of him now but still chasing them for second here in there.