Been researching this for two weeks now, my Blue hippo tang has developed a lump area on one side of its body, is having difficulty swimming, but eating fine. Local fish store is guessing internal parasite or bacteria or worse case some sort of tumor. I have not QT the fish yet, none of the other fish in my reef tank are affected. I bought this fish just a month ago and there was no sign of disease initially. Anyone ever see anything like this before?