Hippo tang flashing

[Jedi Knghit]

I have a hippo tang and royal gramma that have gone through 14 days of copper power at 2.0-2.1 then transfered to a new QT. I followed that up with two rounds of GC in the new QT.. The hippo has been intermittently flashing the entire time, and the royal gramma has not flashed once. A FW dip of the hippo confirmed no flukes, but the flashing persists. No visible marks or spots on either fish. I am at a lose. Any suggestions on how to proceed?

 

[Katrina71]

Video?

 

[Jedi Knghit]

Not likely to get any video right now as both fish are hiding after FW dips. It is pretty clear when it happens, the fish rubs one side of its face against the edge of the PVC pipes in the QT and it will happen a couple times in a row.