Will koi fish and fantail fish get along?

Koi fish and fantail goldfish can coexist in the same pond or aquarium, but there are some considerations to keep in mind. Koi are generally larger and more aggressive than fantails, which can lead to bullying or stress for the smaller fish. It's important to provide ample space and hiding spots to reduce aggression and ensure the health of both species. Additionally, both fish prefer similar water conditions, which can facilitate their coexistence.