this is a two part question, I have a giant king tiger pelco that had a small tear in his dorsal fin a few weeks ago, today the entire fin is completely frayed. Is this fin rot or some thing else. And two, I have him in a 55g with about 30 babiy mollies, How do I treat him without hurting the babies? I do not have a qt tank big enough to hold him the best I coud do is put him in my bath tub. Also will the babys get the fin rot if that is what it is?