The name Coach Feratu was an alias he used while being around humans. His real vampire name is Balik Alistane.
Coach Feratu's last name is taken from the word Nosferatu, which basically means vampire, and was first popularized in works such as Bram Stoker's 1897 novel "Dracula" and the 1922 film "Nosferatu: A Symphony of Horror".
Coach Feratu's vampiric activities first came to light when one of the school's lunch ladies was found dead in the gym with symptoms of a vampire attack. After finding out that vampires do exist, Summer asks Rick if he could turn himself into a teenager, come to the school, and help hunt the vampire down. Rick berates Summer for suggesting the idea, but later does it anyway when he turns himself into Tiny Rick.
Tiny Rick, Summer, and Morty eventually end up killing Coach Feratu by the end of the day.
Later, upon hearing the news of Coach Feratu's death, the Vampire Master was more shocked that Coach Feratu would name himself after a movie and wrote it off as a lame joke, and decreed that any alias used would be real names from then on.