So I woke up this morning to a tank full of dead fish. I have no idea what happened. It is an established tank with all adult fish of different species. I am devastated, I don't know what went wrong. I did a water change yesterday just like normal and the only thing that I can think of is that there was something abnormal in the city water that killed them. I always use Stress Coat and yesterday was no different. The only fish that survived is the pleco. He is not very big but I was wondering if anyone has ever had a pleco go crazy and kill all of their fish? I don't know, I am just trying to fathom what could have happened. Does anyone have any ideas? By the way, the fish were an assortment of African cichlids. A peacock, a large male venustus, a dolphin, an ahli, and a couple mbuna. There was never any aggression shown other than normal cichlid stuff. I just can't figure out what would kill all of my fish except a pleco. Any ideas would be appreciated.