Help! Brooklynella?

[ChelseaBidwell]

I have 2 Royal Gramma Basslets, and a Zebra Barred Dartfish in QT# 2. They have all underwent a 14-day 2.0 ppm copper treatment in QT# 1 and were transferred over to this sterile tank on 9/22. Since then, they have been treated with GC in the water column (we follow @HotRocks 's QT procedure to the T). They have all also had their food treated with GC, Focus, and Metroplex since they arrived. Today I noticed this little guy with white splotches, what looks to be fin rot, and he isn't moving besides somehow still breathing. Is this Brook? If so, can someone help me to figure out where we went wrong? Is 2.0 ppm Copper Power not high enough to treat Brook? The other 2 fish aren't showing symptoms yet, but are all currently in RRR. Is there anything else I can do? Do you think he is too far gone to save? The only thing I can think of is that 3 more wild caught fish arrived 2 days ago and are currently being treated in QT# 1, however, we take every precaution to make sure not to cross contaminate with equipment, feeding, etc..

 

[ChelseaBidwell]

He died Better photos attached.

 

[Ajayabb]

That’s terrible. Sorry about that. Sounds like things went sideways very quickly. Could be Brook or Velvet but I will let someone much smarter than me chime in.