In my experience i have found it sometimes more of how you go about it. for instance if you had any type of pleco and they where established in the tank. then added small cichlids that grew up with the pleco. they leave it alone most of the time. but if you add a pleco to the tank now that it's convict territory may just be a punching bag. Convicts can be relentless when breading too it may not work regardless of type.
mainly what size tank. not only to see if it would have a chance to get away from the cichlids but to see what options you even have for a pleco