But researchers from Murdoch University in Perth, Western Australia, have tracked these huge fish travelling hundreds of kilometres in just a year.
Goldfish are native to eastern Asia but are now a common pet around the world and considered one of the worst invasive aquatic species. Once released, they can have a big impact on local ecosystems.
Dr Beatty says the team found many goldfish which weighed in at over one kilogram, while the biggest was measured at 1.9kg (4lb).
“Our research discovered the fish displayed a significant seasonal shift in habitats during breeding season, with one fish moving over 230km (142 miles) during the year,” says Dr Stephen Beatty, from the Centre of Fish and Fisheries.