Too many fish suppliers and stores are treating their fish with sub-therapeutic levels of copper to suppress disease like velvet, ich, etc. The problem is that you take home the fish and within a few days up to 30 days, disease like velvet comes roaring back "without" the usual visual symptoms. The fish's gills are overwhelmed by the parasites unseen to you. The fish literally, suffocates within hours. Velvet and bacterial infections are rampant in the industry right now. Not good. Because of this, "consider" beginning treatment as if the fish has active velvet. Sorry for the loss of your beautiful fish. Sad.