My tiny biota angel went through 35 days of copper, prazi and metro quarantine like a champ. Now he is in my display tank with 3 other tangs 3X his size and they don’t touch him because he is so assertive. And he is still quite small. The point I’m trying to make is they can go through quarantine just fine.And old post but should you buy another just note biota does not recommend qting there yellows. Probably the only fish I didn’t not qt on my new build. But will leave that up to you.
As for just thinking out side the box hear. How much are your temps swinging on that breeder. April can be pretty aggressive in swings from day and evening temps which can carry over to the tank itself especially smaller tanks depending on how you conditioned your house is.
https://www.reef2reef.com/posts/8999443/bookmark
Of note, after my first prazi dosing he developed swim bladder imbalance. I did a 50% water change the next day and it corrected. I’m not sure if they are related but it was the only hiccup I had.