Question about quarantine tank

[Hilltopreef90]

I recently placed a Royal gramma into my quarantine tank, I’d not added any Cooper type treatment to the tank yet and about a week after I’d placed it in the tank it died, prior to finding it floating and barely alive it was eating and behaving normally ‍
no outward signs that any disease killed it.
My question is do I need to drain the tank completely and start over ?
I tested all the salt level and there’s no ammonia present, I’d previously had a tailspot blenny in the same quarantine, I cleaned and did a 20% water change after I moved the blenny into my main tank and he’s doing fine.
Since I have no idea what killed the Royal gramma I’m hesitant to use the quarantine tank again

 

[vetteguy53081]

I recently placed a Royal gramma into my quarantine tank, I’d not added any Cooper type treatment to the tank yet and about a week after I’d placed it in the tank it died, prior to finding it floating and barely alive it was eating and behaving normally ‍
no outward signs that any disease killed it.
My question is do I need to drain the tank completely and start over ?
I tested all the salt level and there’s no ammonia present, I’d previously had a tailspot blenny in the same quarantine, I cleaned and did a 20% water change after I moved the blenny into my main tank and he’s doing fine.
Since I have no idea what killed the Royal gramma I’m hesitant to use the quarantine tank again

Unless you had disease, no need to drain however if empty - you can

 

[Glenner’sreef]

When all is well try thinking outside the box. 1. A power outage? Loss of oxygen. 2. Something accidentally sprayed into tank? Windex, Lemon Pledge etc. 3. Bug spray? 4. Temp/salinity? Not acclimated properly from original water. 5. QT tankmate aggressor? 6. Stress being sole QT resident? Good luck. Sorry to hear.

 

[Hilltopreef90]

I want to use it again to replace the gramma, since I’m not sure why it died I wasn’t sure about adding a new fish ‍
I figured I’d test all the parameters I can do a 20% water change and in a week or so add another fish