From Longman Dictionary of Contemporary Englishgoldfishgold‧fish /ˈɡəʊldˌfɪʃ $ ˈɡoʊld-/ noun (plural goldfish) [countable] 
HBFDHPa small shiny orange fish often kept as a pet
HBFDHPa small shiny orange fish often kept as a petExamples from the Corpus
goldfish• A stupendous cinema epic, reduced to a sort of frantic scurrying in a goldfish bowl, might merely seem ridiculous.• Small live fishes such as guppies and goldfish, or ground fresh shrimp, should be fed.• Because goldfish will eat new plant growth, use fast-growing varieties, such as Elodea canadensis, Ludwigia and Vallisneria.• If looked after correctly, and given suitable conditions both goldfish and Orfe will live for 10-20 years in a garden pond.• The fairground goldfish has been the starting point for many hobbyists.• All the fish are fed on Hikari goldfish food or cichlid food.• But the other night they went to a carnival at Amphi and each won some goldfish.• Surviving in this goldfish bowl of publicity would crack the strongest union. 