cpo and cajun crays are not the same, assuming the orange cray you speak of is a cpo and not a larger orange cray, big crays pretty much always destroy plants and shrimp and try to destroy fish with varying success, from what I understand.
cpo I hear mixed reviews, but cajun crays I've had no problems with. I would keep that in mind before adding a crayfish because not all species are the same even when they seem similar.
Thanks for the info. I'll do some more research if I decide to get any.