I have that plastic fish that sings annoying songs. I think the rest were burned in a heap downtown back in 2003. That makes mine the only one on town. But don't tell anybody I own that darn thing. They'll take it for kindling in a heartbeat.
Srsly, though? Probably either my short-body jade goby or my platysilurus malarmo/mucosus. Almost everything else I own could appear on an import list from time to time. My 9" orinocodoras eigenmanni, she's rare for her size but not as a species.