No the torn fins is from whatever is wiping the fish out I believe cause the flame angel has some nipped fins and he is the only one with something still on him and all the other fish that died their fins were also nipped up
So you think you have fin rot in your tank along with other disease? I highly doubt this as fin rot usually develops from an unkept tank with bad parameters resulting in very poir water quality. I think what happened is your fish matured over the last year or two and the crowded conditions resulted in stress and aggression. Now combine this with the recent addition of a new large fish possibly ill because no QT was done and you have a recipe for disaster as you are experiencing now. I feel bad for you and hope you can make some informed decisions in the future after your tank has fallowed for the required period of time.
