I'm so sorry for your loss. I hope the others will continue in good health. You worked hard trying to help your little critters. Stay on top of things and keep a sharp eye on the health of the others. Wishing you the best.
Sadly, part of the learning experience sometimes involves the deaths of the fish. Like I said earlier - it's part of the process/risk. No matter how well we take care of the tanks - disease does crop up from time to time. Good luck with the others.