I was treating my beautiful tank of all female Betteas. I lost one, because it had fin rot with an eye half out. I probably should have just taken that one out and treated it. But I treated the whole tank, cause I was worried that they could all be sick and not showing it yet. (I think the eye thing happened when it was trying to get itself underneath everything and anything, when I first noticed the tail starting to split.) The rest look fine. I changed 25% water on 5th day. But still put in a dose after the WC and dosed on 6th and 7th days too. Am trying to figure out where the fin rot came from. I do 25% WC 2 times weekly, treat it and also put the 'Good' bacteria CYCLE in also. Can it have come from an old fish tank ornament? I normally boil things before adding them as decore. But I added some plastic plants from a tank I had years ago.(It was dry, stored in a zip lock bag). I figured if I tried to boild it, it would melt or just break down the chemicals in the plastic, so I just washed it under hot water for a while and let it air dry. What do you ppl think?