Heather Angel / Bubble eye goldfish (Carassius auratus) with upward pointing eyes and two large fluid-filled sacs.. In captivity, Shanghai Zoo, Shanghai, China.

Gary K. Smith / Goldfish (Carassius auratus) in plastic bag acclimatising to an outside pond. Norfolk, England, UK, August.

Will Watson / Crucian Carp (Carassius carassius), amongst Hornwort (Ceratophyllum demersum), Worcestershire, England, UK, March. Captive, bred for re-stocking.

MYN / Paul van Hoof / Goldfish (Carassius auratus auratus) adult, The Netherlands, June, Meetyourneighbours.net project

MYN / Niall Benvie / Goldfish (Carassius auratus) introduced species, Burgundy, France, April.

Alex Mustard / Thermal pool filled with water that remains close to 30 degrees celsius all year, and is able to support a population of fancy goldfish (Carassius auratus) despite being close to the Arctic Circle. Hu...

Jane Burton / Common mirror carp {Cyprinus carpio} in foreground, Crucian carp {Carassius carassius} in background, active in very dim light, UK, captive