dang I'm sorry to hear that! We all go through those loses. Not every fish will make it out of QT.
It's commendable that you're trying to do this right & it's such a hard hobby.
Sometimes for those sensitive and hard to QT fish, observation and diverse feeding is enough for the first few weeks/month. Some people only medicate fish if they see signs of disease. Unless the particular species is a magnet for disease, Like Chromis or Damsels with Uronema....Or tangs with Ich.
The weird thing with QT strategies is that a fishes' immune system will likely be weakened after going through any meds...so those vitamins are important in my opinion.
It's great that the fire fish has started eating! That's the hardest part with any new arrival.
Keep it up with regular light feedings with that guy. After a few weeks, if you don't see any signs of disease I'd add them to the tank if they've put on some weight.
Moving forward I would create list of your dream stock list of fish and plan out the order to add them. For example, if you get another flame angel. Add them last! The purple fire fish is very gentle, so little guys like that should be added before any other more aggressive fish.
Your tank looks like it has a lot good coral growth and coralline algae. I really struggled to get that right in the first few years of being in the hobby. Looks like you're headed in the right direction.
For future QT plans, I always refer to Humble Fish and Dierks on
this platform...Those guys are really skilled in IDing disease and recommending QT protocols. They also have a list of QT vendors if you want to just skip the meds yourself! It's pricey though.
