My poor little cowfish, please help!

[potzy]

Hi,
I currently have 5 fish in quarantine using cupramine. All the fish look to be in excellent condition with exception of this little guy (Cowfish).
He is by far my favourite as he has the most character I've seen in any fish.
He would be no more than 1cm in diameter and still a baby(0.4 of an Inch). He has certainly not lost his appetite or active behaviour.
Could someone please help me with this disease, I have no idea what it could be?
Cheers,

 

[potzy]

Well, the poor little guy didn't make it. I'm not sure if it was the heater or the disease that killed him. I found him stuck between the heater and glass, who knows.
Damn bloody shame really.

 

[pelochas]

probably was a burn on his side. dont really know.

maybe this time the heater got too hot for the lil guy

sorry for your loss

in the future placce the heater in a sump if possible or add a screen around it