for the record, yes, exotics vets deal with exotic animals - that includes fish, the small mammals like rats, ferrets, mice, chins, hedgies, etc, birds, lizards, amphibians, and sometimes zoo-type animals and wildlife. not dogs and cats - they are considered small animals (dogs, cats).
in terms of the ear - at 6 months, how long has he been out of the tape? you may be able to get away just taping the ear again until it stands on its own. however, if it does not stand that way you could consider the implant that jessica mentioned above. just be forewarned that there are implications there.
could you post a pic, maybe that would get you some more detailed advice?