Firefish Currently Dying - please help me

[SurfTrack]

Hello. Fish RARELY die in my tank. I have a 90 gallon red sea mixed reef. No dangerous or aggressive fish. Its been up and running for over a year and is flourishing.

I purchased two small firefish last week and added them to my system with proper hour long drip acclimation. I even managed to feed one of them during acclimation. The day after I added them into the tank - one disappeared. Never found a body or anything. Today, almost a week later, the remaining firefish is having a very tough time breathing and darting around all directions on the sand bed and has now stopped moving. I thought it was time to euthanize, as I was taking the fish out I realized it had more strength than expected so I transferred him to the refugium where he promptly darted directly into the massive ball of chaeto. Good news I hope?

Is there anything I can do to save this fish? Any ideas why the other one died and this one is struggling?

Anything helps, thank you.

 

[hds4216]

Could be disease. Were they swimming in the path of a powerhead or did they have any white specks? Alternatively, were they being bullied? Firefish are very gentle and easily pushed around.

 

[SurfTrack]

Could be disease. Were they swimming in the path of a powerhead or did they have any white specks? Alternatively, were they being bullied? Firefish are very gentle and easily pushed around.

Not at all. I specifically chose these ones due to the fact that they had perfect fins, clear eyes, and no visible flukes or ich. But I do not QT so I guess it is possible, but I have not noticed anything. Also I have not seen any of my fish even take a second look. I never really got them to eat though, but could they really have starved in less than a week?

1 Yellow Tang
2 Clowns
2 Cardinal Fish
1 Royal Gramma
2 Chromis
1 Valentini Puffer