One of my little fellas has got fin rot, he looks awful I'm so worried about him. I have read that fin rot is due to stress - I clean them out regulary every few days, and 100% once a week so it can't be bad water conditions, but I have noticed he hates his new filter. My other two are fine with theirs but he really can't stand the current at all - it's only a small filter with a low current, but it drives him mad. So I have removed it, am I right to do this - can he live without a filter. He seems so much calmer now without it. I'm so worried about him though. I'm adding Melafix - is there anything else you recommend.