I'm so sorry this happened. From the way you handled things you're going to be a great success in the hobby. Welcome.
Not sure what caused Ember's illness...
... in the case of my poor fish warming temperatures most likely caused fungus. We all think about heaters, we worry our babies will get cold....i live in Texas and try to save money so hold off on AC as long as I can. We also have extreme weather fluctuations. Well, with a heater still in place, and my negligence, my tank got too warm......
Just thought I'd throw that out there.
♡