Damsel with a rapid Bacteria Infection

[GoodKat]

Anyone ever had a bacteria infection take out a damsel over night?

I moved him to a new tank Friday. Sunday noticed some missing scales but that he just got beat up in the move. Monday he looks like this. I'm trying to save him with a rally bath.

He' not a new fish and none of the other tank mates are new: royal gramma, falco hawk, firefish. So I ruled out Neg gram. But maybe it was always in the tank? I've never had a bacteria attack this bad and rapid and the tanks are over 1 year.

Can anyone suggest what I'm dealing with? I'm worried about the other fish .

 

[EmdeReef]

It’s certainly possible for this to happen overnight even without the gram negative infection.

Was there any aggression by the more established tankmates? My guess would be something stressed the fish and that enabled bacteria to attack. Going forward consider using an acclimation box, also can be good to add the fish at night or turn off the lights after introducing a new fish for a day or so.

Sorry for your loss