Are black goldfish just called black goldfish or do they have a special name? It sounds a bit silly saying black goldfish, but I would really like to find out the name of them (if they have one that is).
What else would you like them to be called? A black goldfish is a black goldfish, they can be black moors or black ranchus or black fantail, but yeah they are black goldfish.
any animal that is excessivly black (when not normerly) is called
Hypermelanistic (hypermelantino [hyper-melan-tee-no]
usually just referred to as melanistic).
therefor you have a hypermelantistic goldfish or a hypermelantino goldfish.
however all goldfish are born black so it may change colour when it matures.