Goldfish (Carassius auratus)

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Common Goldfish

Carassius auratus


75.708 liters
75,708.236 mL
75.7 Litres (20 US G.)

35.56 cm 20.3-35.6cm (8-14 ")




6.5 - 8.0

283.15 K
50 °F
509.67 °R
298.15 K
77 °F
536.67 °R
10 -25 °C (50-77°F)

5-25 °d

1:2 M:F

Very Common

10-35 years

This animal is available captive bred


Additional names

Fantail Goldfish, Common Goldfish, Comet Goldfish, Shubunkin, Fancy Goldfish

Additional scientific names

Carassius auratus auratus


Goldfish are ornamental fish and not found in wild waterways, unless they have been introduced. The real origin of the Goldfish is debated, but it's most likely ancestor is the Crucian Carp.


Males develop breeding tubercles on their gill covers and on the leading ray of their pectoral fins. Females may have rounder convex vents while males have thinner concave vents. It is only possible to sex Goldfish when they are mature (over a year old) and usually only when it's their breeding season, which is in the springtime (although it has been known for some fish to show signs at other times of year).

Tank compatibility

It is generally recommended to keep Goldfish in a species only tank as they can be bullies, nippy or victims to other fish as they are slow moving and the Fancies are delicate due to their stunted and deformed bodies. Fancy Goldfish should NOT be mixed with Common/Comet type Goldfish for this reason, a Common type is capable of injuring or even killing a Fancy, as well as out competing it to food.
Common Plecos are NOT good tankmates for Goldfish as Plecos are not only tropical fish but have a difficult time getting enough to eat and, given they are nocturnal, they may also latch onto Goldfish while they are sleeping. This will harm the Goldfish and leave it open to infections and parasites.
Other Catfish such as Otos and Corydoras also do NOT make good tank mates. Otos can develop a taste for a Goldfish's slime coat, as can many other suckermouth catfish and Loaches, but both these types of fish can also be eaten by Goldfish. Both Otos and Corys have spines, poisonous in Corys, which can cause them to get lodged in the throat of larger fish, including Goldfish, causing the death of both.


Goldfish are omnivores and should be fed a balanced diet that includes fresh foods. Select fresh foods that are low in starches and sugars, e.g. shrimp, oysters, crab, clams for protein and vegetables such as peas, green beans, lima beans (butter beans), greens (e.g. spinach, collard, mustard, turnip, kale), squash, etc. They will also benefit from occasional live foods like worms, snails, small insects and aquatic plants (e.g. duckweed, azolla or salvinia) and algae.
When feeding Goldfish pellets or flakes, do not feed it floating on the surface, it must sink before it's safe for the Goldfish to eat it. Gulping air at the same time as it eats the food can result in serious digestive disorders.
Note - Fancy goldfish have a distorted indigestion system, so need food which is low in protein, starch and sugar as they get older. Constipation is a real concern with these type of goldfish. So be very careful that you don't over feed this fish. Never give it more than it can eat within a few minutes. Try the gel diet foods like 58LK or 5ML6 which are excellent.

Feeding regime

Adults - Two or three mouthfuls per fish, twice a day.
Fry and juveniles (Tosai to Oya)- feeding multiple small high protein meals promotes growth.
For outdoor goldfish, when temperature drops to below 10°C (50°F) do not feed.

Environment Specifics

Goldfish should NEVER be kept in unfiltered bowl environments. This is not a suitable home for any living creature.
Fancy Goldfish need at least 75.7 Litres (20 US G.) per Goldfish and Common Goldfish need at least 208.2 Litres (55 US G.) per goldfish. If well cared for, Fancies can get around 20.3cm (8") long and Commons over 30.5cm (12"), so adequate room for swimming and turning is also necessary. For this reason, Commons do best in a pond environment.
Common Goldfish can be kept outdoors if the pond doesn't freeze or drop below 5°C (41°F) . Fancy Goldfish will not tolerate colder temperatures as they are more delicate (more prone to fin rot) and will prove to be easy picking for passing predators such as Herons and domestic Cats.


Very sociable and generally peaceful, except when spawning. When spawning, males chase and bump the female causing her to release eggs which the male fertilizes. Attention to water quality is important after spawning as it may cause ammonia to spike from all the protein in the water.


See the pictures and descriptions below for all the different varieties of Goldfish.

Fancy Goldfish

Short-Bodied and Double-Tailed.

Veil Tail

Ryunkins (Ryukin)


Telescope/Globe Eye


Panda Moor

A relatively new morph of the Black Moor above. Features all the same characteristics, the only difference being they are black and white, giving them their common name.

Fan Tail




Hamanishiki/Crown Pearlscale


A cross between a Ryukin and a Telescope. They have a high arched back with telescope eyes.









Common Goldfish

Long-bodied and single-tailed fish

Common Goldfish

Comet Goldfish

"Shubunkin" Goldfish

Special notes

  • If your Goldfish cannot swim or is having problems staying upright, this is a sign of constipation having effected their delicate (and deformed in Fancies) swimbladder. If not caught early enough this can prove irreparable and even fatal. Feeding of natural fish laxative such as cooked de-shelled pea followed by a day, or several days, without food can help. Overfeeding is the prime cause of swimbladder disorders.
  • A group of Goldfish is called a troubling.[2]
  • Shubunkins are actually called "Chuwenchin" in China. But European importers got the name wrong in the 19th Century and it stuck.[3]
  • The fleshy growth or hood covering of some varieties of Goldfish such as the Oranda is called a Wen.

Identification & Pictures


Common Goldfish: Fancy Goldfish on show at Aquarama 2007: Bristol Shubunkin at fish show:
Lionhead X Buffalo Ranchu at Aquarama 2009: Orandas on show at Aquarama 2009: Fancy Goldfish on show at Aquarama 2009:
30.5cm (12") 3 year old Feeder Goldfish:


  1. Chinese Goldfish - Dragon-eyes
  2. San Diego Zoo - Animal Group names
  3. Aquariums Life Goldfish Profile

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