I picked up a discus fish that was sick and dying at the LFS, as they didn't know what they were doing. It has hole in the head, I believe, cause by hemi. I am going to treat it with metronidazole, and I was wondering if this med would harm my other fish, plants, or invertebrates? Anyone have any advice as to dosing schedule and water change. I was thinking 400 per 10 ghallons, after a 30 percent watyer change, followed hours later by a 25 percent change and redose. Thinking of repeating it for a few days, but I don't know if it will happen. Any advice?