Chromi changed behaviour

[rpkneumann]

Started with 7 chromis. 1 found dead after3 days without obvious injuries another simply disappeared. Now this one is swimming nearly upside down breathing a storm and eyes a bulging.
Tank levels normal. Tank is 90 days old.
Video:
Chromi sick?

Should I take him out?

 

[Jay Hemdal]

Started with 7 chromis. 1 found dead after3 days without obvious injuries another simply disappeared. Now this one is swimming nearly upside down breathing a storm and eyes a bulging.
Tank levels normal. Tank is 90 days old.
Video:
Chromi sick?

Should I take him out?

The chromis looks like it has good body mass, but it is breathing WAY too fast. Removing it now won't protect the other fish from what it may have, since they are already exposed. My concern here is that it might be Amyloodinium/velvet. That needs to be treated with coppersafe in a treatment tank.

 

[rpkneumann]

Put Chromi in my qt tank. Completely lost orientation breathing still fast but more and more less active. 2 hours later it stopped breathing.
I could not find any external damage or parasites on it.
The rest of the chromis and other fish are fine.