Can fancy goldfish be mixed with tropical fish?
Fancy goldfish should only be kept with other fancy goldfish. The only reasonable exception is white cloud mountain minnows, which are small, peaceful cold water fish. Although they can tolerate higher temperatures they will prefer to live at 17-21C. Some cool water fish can be found, for example guppies, platys and danios, which have been acclimatised to cooler water, this does not make them suitable tank mates for fancy goldfish. Many of these cool water fish are quite boisterous and can worry the slower fancy goldfish as well as stealing all the food. There is also a chance when mixing species of introducing diseases to which the fancy goldfish will not be immune.
