I wouldn't call those "comets". Comets are more streamlined, with longer tails and more slender bodies. These just look like two plain ordinary common goldfish. I know it comes as a shock, but most goldfish aren't anything other than goldfish. People want to look at every goldfish they see and assign it the name of some accepted breed. All goldfish are the same species (Carassius auratus) and the vast majority of them are just plain goldfish.
It's like seeing a street dog in a Caribbean country, or an Indian village, or an African marketplace. They all look pretty much the same, and they are all the same species (Canis lupus familiarus). Sure, some carefully-bred dogs are Greyhounds or Dachshunds or Mastiffs or Poodles or whatever...but for every purebreed there are hundreds or thousands of just plain mutts.
In both cases, people want to call them something special because they don't care for the idea of owning a Just Plain Mutt.