I really can’t have a quarantine tank I don’t have any spaceI’ll let the experts chime in
I know it’s tempting to act fast, but as said above wait for one of the pros to get a proper diagnosis on the issue so we don’t stress the fish out with the wrong corrective actions, but what we can do in the meantime is….
Get another quality picture and videos incase needed, and start prepping for a qt setup.
Wether a bin or a cheap tank get it set up with water, heater, flow and some pvc.
If one fish is getting treated then they all are getting treated and the tanks going fallow!