Bartlett's Anthias with dark patch

[Akrite]

I got 5 Bartlett's Anthias that were QT with prazi then copper for 5 weeks. One of the small Bartletts has a dark patches around the dorsal fin. Is this a fungus and if not what and how can I treat it?

 

[Akrite]

Any one?

 

[reeferbro0622]

Doesnt look like any kind of fungus to me, none of my fish showed symptoms like that except when I have a fish that darkens in color, reading an article in tropical fish magazine it said that fish can dull in color from being under high powered light... Is it still eating acting healthy? if so I wouldnt worry

 

[Aquanaut of WA]

Possible bacterial fin rot due to copper reaction. I've read that they are sensitive. May need to add a slime coat protective to water. Also they do not tolerate Salinity below 1.020. I have 1 out of 7 survive because no one told me their sensitivity. They died within a day or two of reaching 1.016, as I attempted to reach hypo salinity. Also check PH. They prefer 8.2-4. Have a LFS test water perams and tell them that you are treating Anthias.