Good luck finding crassipinnis, they haven't been around for a few years now. My friend (a fairly large importer) has been trying to get 'true' crassipinnis for atleast 3 years. He was close last year but with no luck.
Orbicularus is alot of the same but is more readily available then the crassipinnis. I think Rapps was the last one to have these in (and I kicking myself for not buying then). You'll have to just watch the net and jump on the next bunch that comes available.
If you find some please give a shout in p.m's as I've been wanting both for a long time. If you find a reliable source for crassipinnis please let me know, as I know several people that are interested in this species.
Good luck.