FRT count? If not then I've seen a few XB arowanas at an exhibit in Shark Reef @ the Mandalay Bay Casino.
At least two of the piranhas I've owned in the past were considered rare; one of them almost non-existant in the hobby. The one I own now is also quite rare, I have a thing for rare characins.. lol
What types of pirahna were these?
Serrasalmus Eigenmanni, and Serrasalmus Altuvei. The One I have now is a Serrasalus Spilopleura "Ruby Red Spilo" there are pics in my profile album.
they're not that rare!
I have a short bodied peru monoculus cichla I have never once seen these available or heard of anyone ever owning them.