Well I had a ich on my powder blue first time in half a year all other fish looked fine . So I used garlic/plus kent food supplements, brine,live brine, PE Miyses,nori ect...
He was like a pig ate all day fought it for 4 weeks and ate till the day he passed away I took a nap and woke up with him in the rock
So why he pass away I don't know have flame and six line wrass that where fairly new to the tank. Maybe the six line ?
But he's the only one that passed away now I'm just keeping an eye on everyone else.
I was going to qt him but people said more stress leave in tank and just feed.