HELP Tang dead during QT | Post-mortem

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Hi reefers, first post here on this forum, I have a QT up and running with 5 tiny fishes 3x blue chromis and 1x sleeper goby x1 blueeyed kole tang, well 4 now, I lost my tang this morning and wanted to get some insight to try and understand what it had and be better prepared to approach such situation in the future. So the tang was pretty active and feeding well a couple of weeks ago when I got it from my LFS, introduced it to the QT with four other fish on a Saturday evening, Sunday morning the tang was covered in white spots. (For the record, the QT is established, started it with water from DT and a lot of cycled bio media as well) . I usually run a round of Prazi for 7 days before starting cupramine but I started cupramine straight away and raised the levels to 0.5ppm over the course of three days. Tang seemed fine for nearly two weeks, eating a lot and active, last night got home from work and he had a white mucus in his mouth, was lethargic and not eating, dead this morning. I don't think whatever he had came from my DT as it has currently only three fish that had been QT'd before over a month with Cupramine and Prazi and they all look fine and healthy. I think it was some sort of bacterial infection as I saw some white slime around his gills and black mucus in his fins. My intention is to try and understand what happened to be able to treat it in the future if/when it happens again, also should I be worried with my other fish in there? Thanks everyone.


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Dr. Fish
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Sounds like the tang got a secondary bacterial (mouth) infection: Bacterial Infections

This is common when a fish's immune system is already battling a parasitic infestation, and is made more complicated by the fact that copper is an immunosuppressive. The only thing you could've really done is get him out of copper and treat with an antibiotic: Antibiotics

IME; Nitrofural + Sulfa work best on mouth infections.