Aquabid

It functions exactly like eBay, with user accounts, a feedback mechanism, and a buy-it-now function. (The only missing function is the ability to run Dutch auctions.)

Aquabid is an excellent tool for the serious aquarium hobbyist. Sellers, wholesalers, and transshippers from all over the world offer exotic, rare fish, invertebrates, plants, and aquarium supplies.

For some rare species that never appear in local fish stores, such as zebra plecos, Aquabid is the only source of these animals for the average hobbyist. Other popular, and now common, species such as the asolene spixi snail, crystal shrimp and celestial pearl danios ("galaxy rasboras"), owe their success in establishing a foothold in the U.S. were largely Aquabid.