Stark Raving Mad (1999)

Season 1: Episode 6

Audrey and her flaming French partner, Cesar, throw an extravagant dinner party, and invite Henry and Tess with the sole purpose of getting them to bring Ian. Ian hates parties, so Henry has to beg Ian to do him and Audrey a favor and go anyway. But Tess gets food poisoning from bad sushi and has to cancel, leaving Henry with no choice but to bring Maddie as his date. Ian gets bored at the party -- where he is hounded by a phony 20th Century FOX executive, Danny Lukor -- and decides to spruce things up by taking one of Cesar's prized exotic fish and putting it in Henry's drinking glass. From there it's a comedy of errors as Henry, Maddie and Tess (who shows up still sick to her stomach) try to sneak the fish back into the tank without Cesar noticing.