Hello, I have a tank with a community of fish, and one of the six Corydoras has Popeye. I can't afford to get a second tank to isolate it in, so is there anything else I can do? I have been putting in Melafix once a day for the two days since it's started, and I just recently did a water change. Is it contagious? Can it be cured? Any advice would be appreciated.