My daughter was given a goldfish which had been living in a pond. He had some scale loss when she got him which got worse. After a large water change (55 gal.) I haven't noticed any more scale loss and he's very happy. My questions are, will his scales grow back and what caused the scale loss? I've added a handfull of salt (diluted in water) and some melafix. Thanks in advance for any help you can give me.