Overview
"Go Fish" is episode 20 of season two of the television series Buffy the Vampire Slayer. It was written by David Fury and Elin Hampton, directed by David Semel, and first broadcast on The WB on May 5, 1998.
Plot
Buffy arrives at school in a car with Cameron, a member of the Razorbacks swim team. He makes persistent and unwelcome sexual advances, so Buffy slams his head against the steering wheel. Giles informs Buffy that the remains of Dodd, another swim team-member, were found on the beach after a party. The Scooby Gang tries to determine what killed him. Xander bumps into Cameron, who rubs his elite status in Xander's face. After Cameron goes to the cafeteria for a snack, Xander hears him scream. Investigating, Xander finds: a ransacked cafeteria; Cameron's skin; a gill monster (humanoid sea-creature).
In the library, Cordelia sketches the creature that Xander saw. Buffy and Willow return, having been informed that Cameron and Dodd were the Razorbacks' two best swimmers; after them was Gage. Having little else to go on, Buffy shadows Gage as the potential next target. At the Bronze that night, Gage confronts Buffy about her following him; she tells him that he may be in danger. He does not believe her and leaves, only to be attacked by Angelus in the parking lot. Buffy fights off the vampire, noting as she does that Angelus was spitting out Gage's blood rather than drinking it.
The following day, Buffy and Willow and Cordelia sit in on swim practice. They discuss Angelus' behavior, and speculate that the swim team may be taking steroids—which repel vampires, but attract gill monsters. Xander joins the swim team in order to get information from places the girls would not have access to.
From Wikipedia (CC BY-SA 4.0).