During filming, animal rights activists showed up with the intention to make sure all the fish were treated correctly. After viewing the script, and realizing that the title of the film was really more about cheating 'fish' than actually shooting it, they left somewhat embarrassed.
To research their roles as conmen, both Stuart Townsend and Dan Futterman spent time flogging perfume from a suitcase in London's busiest shopping area, Oxford Street.
In the scene where Dylan picks up a toaster from a dumpster, all the extras (all of them males) can be seen pushing prams.