Red Devils i worked out they are bad tankmates when mine killed an oscar and a silver pearch which were both bigger then him. But i whant to know wheather a large armoured catfish such as a pleco could live with him.
No one can give you a definite answer to something like that, you'll just have to try it. But I seriously doubt that RD will accept anything in his tank. Plecs may have thick skin but their eyes, fins and stomachs are still vulnerable. Red Devils are commonly kept alone, they're known for their aggressiveness.