What species are related to fantail goldfish?

Fantail goldfish are not a distinct species themselves but rather a breed of goldfish. All goldfish breeds, including fantails, are descended from the wild Prussian carp (Carassius gibelio).

Therefore, fantails are related to:

* Other goldfish breeds: Like the common goldfish, comet goldfish, oranda goldfish, etc.

* Other Carassius species: Including the crucian carp (Carassius carassius) and the silver carp (Carassius auratus).

While they are ultimately related to all of these fish, fantails are specifically bred from the common goldfish (Carassius auratus) and share the same lineage.