nothing eats vampires but a werewolf bite can kill a vampire
Cannibal. According to the anime series Trinity Blood a vampire who has the ability to eat other vampires is called a Crusnik.
In folklore and mythology, vampires are often depicted as undead beings who were transformed through various means such as being bitten by another vampire, making a deal with the devil, or through a curse placed on them. Different cultures have different legends about how vampires are formed, but the common theme is that they were once human but are now creatures of the night with supernatural powers.
It comes down to your definition of the terms. I usually consider a cannibal to be one who eats flesh for its inherent nutrition. Your stereotypical vampire drinks blood primarily to steal life-force, not nutrition. Some vampires get digestible nutrition from the blood they drink but not all do.
What do you call a human that eats other humans, a cannibal, we're a species of animal so it should be the same.
Human
Carnivore
An herbivore
There are no known predators
The name of the moth that eats blood is called the vampire moth
Nobody knows for sure what they eat but these are a few examples that they have been thought/known to eat shrimp, jellylike animals, prawns plankton, and small deep sea creatures.
There is no such thing as a "vampire goldfish". Except in dreams.well no one or no thing can eat a vampire gold fish because, they will bite it