Depends on ho you define getting along really, I think a chardonay would get along swimmingly with a big cichlid, Lol.
You will soon have some convict heads and spines lying around poluting your tank. If I were you I'd get alot of really small ghost shrimp, at feeder prices ofcourse, maybe just maybe some of them wont get eaten right away and will clean up a bit of the pirahna mess, afte ra certain size pirahnas do stop eating little fish however, wich is nice.