Appart from the temperature issue (as mentioned above carp are cold water species) a single carp has no chance against an aro as it has no form if defence making it a very big feeder or a single dither fish at best , dither fish work best in numbers as its harder to pick out a single fish from a shoal spreading the aggression so theres less pressure on single fish. Your carp already has ripped fins do him a favour and rehome him itll save his life the aro won't give up battering it as theres nothing else to pick on in your tank , if you want tankmates for your aro go with something that can hold its own against attacks , cichlids , bass , catfish etc