I had an Asian red tail cat, looks like that's what did it imo. I remember how the fish looked after the night with him due to my ignorance. Get rid of him. He'll fighht with everyone till he's big enough to take them out. Your smaller fish will be killed sooner, the cichlids, I'd say once he's 12"+ he'll take them out as well. He would've killed a lot of fish if I left them with him for a second night. Had a large pim blochii about a foot, he killed the night of. It was late I remember waking up to the splashing and the pim rear end was mostly gone, wasn't much I could do by then.