Tilefish is sick

[Sencha]

I've had two tilefish in my tank since April 16th. Both have been acting healthy up until today. Last night we noticed that one of the tilefish had what looked like a flap of skin on the side of his face but he was still eating but hiding more than usual. This is what he looks like today...

Any ideas on what this is and if and how it can be treated?
He is in a quarantine tank now.
Any advice you have would be great. This is one of my and my family’s favorite fish
Thanks for your help

 

[Sencha]

So the tile fish died
If anyone has any ideas on what it could have been that would be great. I want to know if I need to do something with my other fish, thought they are not showing any symptoms, this disease seems to move fast.

 

[sasquatch]

so sorry Sencha, it almost looked like ph burn, anyway Lee will be along at some point and can hopefully shed some light on this

 

[Sencha]

Thankyou sasquatch. I tested the pH and it was at 8.3 so I don't think it is a pH burn.
Now for more bad news... our other tilefish died this morning. This one looked healthy and ate lastnight so I'm unsure if both fish suffered from the same illness?

 

[sasquatch]

bacterial infection then? rotten whatever it was

 

[leebca]

This disease has been showing up more and more, lately. It can kill quickly -- depending on how well fed the fish was and how well its nutritional needs were being met.

The proper treatment is to quarantine the fish and treat with Cupramine, making sure to maintain the proper copper level with a Salifert Copper Test Kit or another suitable to measure Cupramine copper. While in this quarantine tank and while being treated with Cupramine, the fish is given a formalin dip every other day for a total of 4 or 5 dips.