Fancy goldfish are true cold blooded creatures and their aquariums do not require a heater, though they should be provided with a filter and an airstone.
To give the Ancient Japanese and Chinese breeders some credit, fancy goldfish of the time were kept in ponds and ceramic vases and viewed from the top, so the round body and strange wen highlighted the visibility and beauty of the fish. Viewed from the side in an aquarium the round body and exaggerated fins and wen can look a bit odd.
Goldfish live for twenty years so they are truly a pet. AquariumFishSale offers a variety of fancy bred species at different sizes from our breeders in Shanghai and Canton.