Ok, so there are a few of these going around right now, but I've got another one! Samson's fin rot is back, and I'm really trying to figure out what's causing this. His water quality is good. I tested it and all the levels are down at 0 where they should be, and I do weekly 25 -30% water changes, so I'm not sure if its water. But could this be from stress? Last time I treated him with Maraycn-2 and it stopped getting worse and started to get a bit better, now its back and I'm wondering if I should use the same med or try something else. How long should he take to get better and start regrowing his poor fins?