Comet Goldfish

Looks how to spot one

Scaled, single-tailed slender body with a long forked tail

A sleek, streamlined goldfish, a little smaller and slimmer than the common goldfish, with one dorsal fin and a single tail that is long, deeply forked and finishes in sharp, well-spread points. The tail is the star feature: show standards ask for its leading edge to reach about three quarters of the body length, and the other fins are longer than on a common goldfish too. Scales are usually shiny metallic, though calico comets with mottled nacreous colouring also exist. For showing, the body should be at least 7.5 cm long.1234

Personality what they are like

Peaceful but full of energy. Comets are among the most active goldfish, often zipping back and forth as if playing, and they stay bright and alert. Like other goldfish they can learn to take food from their keeper's hand and recognise feeding routines.136

Daily activity how busy a day looks

High. Comets are fast swimmers that need long, open water to move around in, so a large tank or, better still, a garden pond suits them best. They are often kept outdoors alongside koi.136

Grooming and care the hands-on bits

Coldwater fish that normally needs no heater. Aqueon recommends about 16 to 21 C (60 to 70 F) for comets, while Wikipedia gives 20 to 22 C as the general goldfish optimum; comets cope with cooler water than fancy goldfish. pH guidance ranges from 6.0 to 8.0 (FishBase) to 7.0 to 8.4 (Aqueon). Goldfish produce plenty of waste, so good filtration and regular partial water changes with dechlorinated water are part of routine care.678

Home where they are happiest

Plenty of room: about 20 US gallons (roughly 76 litres) of water per adult comet is the usual guideline, and FishBase gives a minimum tank length of 100 cm for the species. Because comets grow and swim fast, many keepers move them to a pond once mature. A wide tank with open swimming space works better than a tall, narrow one.7681

Food basics what goes in the bowl

Omnivore. Feed a goldfish flake or pellet as the staple, and add frozen or live foods such as brine shrimp or daphnia plus some greens as treats. Give only what is eaten in about 2 to 3 minutes, once or twice a day. In the wild, goldfish graze on plankton, small invertebrates, plants and detritus.689

Company who they like around

Sociable and peaceful with similar-sized fish. Best kept with other fast, single-tailed goldfish such as commons and shubunkins, or with koi in a pond; adult comets can be too boisterous for slow fancy twin-tailed goldfish.61

The story where it all began

Goldfish were bred for colour in China for more than 1,000 years before reaching Japan in 1603, Europe in 1611 and North America around 1850. The comet is one of the few goldfish types created in the West. In the 1880s fish with unusually long, deeply forked tails turned up in the ponds of the U.S. Government Fish Commission in Washington, D.C. Hugo Mulertt, a government worker at the time, later became a commercial goldfish breeder and author and brought the comet to the wider market. It went on to become the most widespread goldfish variety in the United States. Comets were once a much more common sight at goldfish shows than they are now, and top-quality show comets are rarer today, but the variety remains a pond favourite. Colour forms such as the red-and-white sarasa comet, which originated in China, and the calico comet, also called the comet shubunkin, broadened its appeal.71234

Recognised by the official bits

Bristol Aquarists' Society / goldfish-types.info

Published show standard for the comet: slender body about 35% as deep as it is long, single deeply forked tail with pointed lobes whose leading edge ideally reaches 75% of body length, minimum body length 7.5 cm3

IUCN Red List

The species Carassius auratus is assessed as Least Concern (4 August 2010)8

Taxonomy

Single-tailed domestic variety of the goldfish, family Cyprinidae7