2 weeks ago we bought a raccoon butterfly fish. Didn't QT. From the very beginning he was scratching on the rocks. Never showed any external signs of anything. No spots, dots, dust, sores..nothing. And believe me, I looked. On Sun. he died. Now I'm worried for our other fish. We only have an ocellaris, percula, and orange spotted goby. The percula MAY be slightly less active then usual. Params I think are good. Checked just after the butterfly died. pH 8.0, ammonia 0, nitrite 0, nitrate 10. salinity 1.023. 90gal. Would you pull the other fish? We bought a QT. Would you treat? With what?