I have never owned a redtail cat but I know they eat anything. I do however know about snakeheads and there is nothing I would put in there with him. Personal experience I had Two clown knifes each around 12" and a 8" red snakehead. They were all one big happy family for about month. Then one day I got home and one of the clown knifes was gone. All that remained was his head. The other clown knife was hiding in the corner of the tank behind some java moss. I figured maybe I wasn't feeding the snakehead enough so I increased his daily intake of food but 3 days later I came home again and found the mid section torn out of the remaining CK. In a nutshell snakeheads IMO kill just to kill, they don't want anything in or around them. However, I still to this day keep a pleco in with my snakehead, they seem to get along okay.
