Dammit! I forgot Anthony Calfo would be speaking in Brooklyn tonite *cries*
Anyway, we have fish shows every month or so at our local fish club mtg. They're called bowl shows, and folks bring in what they feel is their best fish to be exhibited and judged.
I've never heard of an Aquarium show along the lines of say, one of those home shows or computer shows, but I do know many of the larger fish clubs have annual big auctions.