Common Goldfish

Goldfish

Family: Cyprinidae Goldfish, Common Goldfish, Carassius auratusCarassius auratus auratusPhoto © Animal-World: Courtesy David Brough
Latest Reader Comment - See More
I have a 7yr old gold fish in a 10 gal tank. He is about 8 inches, no other fish, keep tank clean, feed him large flake goldfish food. For the last ten days he has... (more)  ron ash

Goldfish are fun to watch... just look at all the different colors of these beautiful fish!

The Common Goldfish Carassius gibelio (previously Carassius auratus auratus) are hardy fish that are well known by all aquarists. They are colorful, inexpensive, and readily available. These fish are a favorite pet for a multitude of keepers because they can be quite personable and are delightful to watch.

The Common Goldfish is a small member of the Cyprinidae family of carp fish. The popular Koi fish commonly kept in ponds is also a member of the carp family. The C. gibelio was normally a silver or gray color but early in the Jin Dynasty, somewhere between the years 265 - 420, it was noted that there was a natural genetic mutation producing a yellowish orange color.

It became common practice to breed this pretty golden fish, and over time a large variety of breeds of varying shapes and sizes have been developed. Other natural mutations are red and yellow. Today they are available in various solid colors and combinations of white, yellow, orange, red, brown, and black.

Goldfish, Carassius gibelio
Tailfin should be completely split to show

These are one of the hardiest of the gold fish varieties. They have a history of often being the first fish new aquarists will keep. A choice beginner fish because they are one of the easiest fish to keep. They can handle a variety of aquarium conditions and are also not picky, readily eating what is offered. Selecting them is also fun because they have come in such a diverse mix of colors.

Most freshwater aquarium fish are tropical fish but goldfish are an exception. These are coldwater fish, preferring a tank kept between between 65 - 72° F (18°- 22° C). Still, these durable fellows are very versatile and can tolerate tropical temperatures all the way down to a few degrees above freezing, as long as the cooling drops only a few degrees a day. They can be maintained without a heater or a filter, as long as the water is changed out frequently.

These are active fish and they can swim fairly fast, but they are also very social. They thrive well in a community. Along with the other elongated goldfish, such as the Comet Goldfish and the Shubunkin Goldfish, they make good pond fish. They are fast and so can get along well with Koi as well, but they will readily spawn, and so can quickly overpopulate your pond.

If they are kept in a community with other freshwater fish, then the aquarium needs to be designed for the needs of the other fish. Not only will it need a heater, but it will also need a good filtration system. Goldfish place a much heavier bioload on the aquarium than most other tropical fish, so more frequent water changes will have to be performed as well to keep the water quality up.

For more goldfish information, see:
Goldfish Care: Fancy Goldfish and Goldfish Diseases


Geographic Distribution
Carassius auratus auratus
Data provided by FishBase.org
  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Cypriniformes
  • Family: Cyprinidae
  • Genus: Carassius
  • Species: auratus auratus
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Common Goldfish - Quick Aquarium Care
  • Size of fish - inches: 4.0 inches (10.16 cm)
  • Minimum Tank Size: 15 gal (57 L)
  • Temperament: Peaceful
  • Aquarium Hardiness: Very Hardy
  • Temperature: 65.0 to 72.0° F (18.3 to 22.2° C)
  • Aquarist Experience Level: Beginner
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Habitat: Distribution / Background

The goldfish of today are descendants of a wild carp fish, known as the Prussian Carp, Silver Prussian carp, or Gibel Carp Carassius gibelio (syn: Carassius auratus gibelio) which was described by Bloch in 1782. For many years it was believed that goldfish had originated from the Crucian Carp or Golden Carp Carassius auratus auratus described by Linnaeus in 1758, but more recent research is pointing toward the former.

These wild carp originated in Asia; Central Asia (siberia). They inhabit the slow moving and stagnant waters of rivers, lakes, ponds, and ditches feeding on plants, detritus, small crustaceans, and insects.

Goldfish were originally developed in China. This species was normally a silver or gray color, but early in the Jin Dynasty, somewhere between the years 265 - 420, it was noted that there was a natural genetic mutation producing a yellowish orange color. It became common practice to breed this pretty golden fish for ornamental garden ponds.

By the 1500’s goldfish were traded to Japan, to Europe in the 1600's, and to America by the 1800's. The results of this centuries long endeavor is the wonderful goldfish colors and forms we see today. Other natural mutations are red and yellow, and today there are various solid colors and combinations of white, yellow, orange, red, brown, and black. Today domesticated goldfish are distributed world-wide and there are more than 125 captive bred varieties that have been developed.

  • Scientific Name: Carassius auratus auratus
  • Social Grouping: Groups
  • IUCN Red List: NE - Not Evaluated or not listed

Description

The Common Goldfish is an elongated, flat-bodied variety of goldfish. The head is wide but short and it has a smoothly tapering body shape from its back and belly to the base of its caudal fin (tail fin). The caudal fin is forked. Its fins generally stand fully erect and the edge of the dorsal fin is slightly concave.

The average goldfish lifespan is 10 – 15 years, though living 20 years or more is not uncommon in well maintained goldfish aquariums and ponds.

The environment the Common Goldfish is kept in is a determining factor on whether your pet grows to its full potential size or is somewhat smaller. In an average 10 gallon tank, if well cared for and not crowded, they can grow up to about 4 inches (10 cm). In a larger, uncrowded tank they can grow generally reach about 7 or 8 inches (17.78 - 20.32 cm). If kept in a spacious pond they can reach over 12 inches (30+ cm) with some hobbyist reporting their goldfish reaching up to a whopping 18" (45+ cm)!

Common Goldfish
Common Goldfish

There are various solid colors and combinations of white, yellow, orange, red, brown, and black. The most distinguished specimen is a bright orange metallic color.

The Common Goldfish is very similar to, and sometimes confused with, the Comet Goldfish. The Comet is a further development of the Common Goldfish. Both these fish have an almost identical body shape but the fins on the Comet are much longer, especially the caudal (tail) fin, and it is more deeply forked. Also, in the standard orange color the Comet is generally a more reddish orange while the Common Goldfish is more orangish. The adult size of the Comet Goldfish is smaller too. On both these fish the caudal (tail) fin is held fully erect.

Comet Goldfish
Comet Goldfish

Also, in the standard orange color the Comet is generally a more reddish orange while the Common Goldfish is more orangish. The adult size of the Comet Goldfish is smaller too. On both these fish the caudal (tail) fin is held fully erect.

Another goldfish that is almost identical to the Common Goldfish is the 'London' type of Shubunkin Goldfish. Both these fish have virtually the same body and fin shapes, but the London type Shubunkin Goldfish has a totally different body color. While a good specimen of the Common Goldfish will have a bright orange metallic color, this London type Shubunkin goldfish can be speckled or have a variegated color pattern.

Another goldfish that is almost identical to the Common Goldfish is the 'London' type of Shubunkin Goldfish. Both these fish have virtually the same body and fin shapes, but the London type Shubunkin Goldfish has a totally different body color. While a good specimen of the Common Goldfish will have a bright orange metallic color, this London type Shubunkin goldfish can be speckled or have a variegated color pattern.

  • Size of fish - inches: 4.0 inches (10.16 cm) - Average size is 4" (10. cm) but can reach about 7 or 8 inches (18 - 20 cm) if not crowded. If kept in a spacious pond they can reach over 12 inches (30+ cm). Some hobbyist report their Common Goldfish reaching up to a whopping 18" (45+ cm).
  • Lifespan: 15 years - The average goldfish lifespan is 10 – 15 years, but they have been known to live 20 years or more when well maintained.

Fish Keeping Difficulty

Common Goldfish are some of the hardier species of goldfish. They are very undemanding of water quality and temperature. They can do well in a goldfish aquarium, or even a pond as long as the environment is safe and their tank mates are not competitive.

Many people will keep goldfish in an aquarium with no heater or filtration, but for the best success provide them the same filtration, especially biological filtration, that other aquarium residents enjoy.

  • Aquarium Hardiness: Very Hardy
  • Aquarist Experience Level: Beginner

Foods and Feeding

Since they are omnivorous, the Common Goldfish will generally eat all kinds of fresh, frozen, and flake foods. To keep a good balance give them a high quality flake food everyday. To care for your goldfish, feed brine shrimp (either live or frozen), blood worms, Daphnia, or tubifex worms as a treat. It is usually better to feed freeze-dried foods as opposed to live foods to avoid parasites and bacterial infections that could be present in live foods.

  • Diet Type: Omnivore
  • Flake Food: Yes
  • Tablet Pellet: Yes
  • Live foods (fishes, shrimps, worms): Some of Diet
  • Vegetable Food: Some of Diet
  • Meaty Food: Some of Diet
  • Feeding Frequency: Several feedings per day

Aquarium Care

Regular weekly water changes of 1/4 to 1/3 is strongly recommended to keep these fish healthy. Snails can be added as they reduce the algae in the tank, helping to keep it clean.

  • Water Changes: Weekly

Aquarium Setup

Setting up a goldfish aquarium in a manner that will keep your fish happy and healthy is the first step to success. The shape and size of the aquarium is important and depends upon the number of goldfish you are going to keep. These fish need a lot of oxygen and produce a lot of waste.

Good filtration, especially biological filtration, is very helpful in maintaining the water quality of the aquarium. Filtration systems remove much of the detritus, excess foods and waste. This in turn helps to keep the tank clean and maintain the general health of the goldfish.

Goldfish are freshwater fish, but they have some tolerance for slightly brackish water. The salinity level for goldfish must be kept low, below 10% with a specific gravity of less than 1.002.

  • Tank parameters to consider when choosing a goldfish aquarium:
    • Tank size
      Fifteen gallons is the absolute minimum required to house a common Goldfish. It's best to start with a 20 - 30 gallon tank for your first goldfish and then increase the size of the tank by 10 gallons for each additional goldfish. Providing a large amount of water per fish will help dilute the amount of waste and reduce the number of water changes needed.
    • Tank Shape
      Always provide the maximum amount of surface area. A large surface area of water will help minimize goldfish suffering from an oxygen shortage. Surface area is determined by the shape of the tank. For example an elongated tank offers more surface area (and oxygen) than a tall tank. In an oval or round shaped tank the middle offers more surface area than filling it to the top.
    • Number of fish
      For juveniles a general rule of thumb is 1 inch of fish (2.54 cm) per 1 gallon of water. But this rule only applies to young fish and is not adequate as they grow. Larger gold fish consume much more oxygen than young fish so maintaining this formula for growing fish will stunt them, and can contribute to disease and even death.
    • Fish size and growth
      To allow for proper growth, either buy fewer fish than the maximum number or be prepared to get a larger tank. To prevent stunted growth and other health problems, don't overstocking the aquarium.

Goldfish are a cold water fish and will do best at temperatures between 65 - 72° F (18°- 22° C). The Common Goldfish are one of the most hardy varieties of goldfish and can tolerate temperatures a few degrees above freezing, as long as the cooling drops only a few degrees a day. A quick temperature drop can kill them, so if you live in a very cold climate a heater is advisable.

Provide a gravel substrate to help create a natural and comfortable environment for your fish. You can add some decor, but make sure that all ornamentation is smooth with no protruding points or sharp edges. Smooth rocks or driftwood should be used sparingly if at all. Aquarium plants would be the best choice of aquarium decor for goldfish, but unfortunately these fish are diggers. Consequently live plants may be uprooted. Artificial plants make a good substitute and silk plants are safer than plastic ones.

Most aquariums come with a cover that includes lighting. A cover for the tank is desirable as it reduces evaporation and though they are not prone to jumping, on occasion some gold fish will jump out. Lighting is not essential for goldfish, but does make the aquarium a nice show piece and lighting will help if you have live plants.

  • Minimum Tank Size: 15 gal (57 L) - 15 gallons is the absolute minimum for this variety of Goldfish, and 25 gallons is really best. This fish can grow to over a foot in length, keeping it in a small tank will stunt its growth and cause irreversible damage.
  • Suitable for Nano Tank: Sometimes - A Nano tank is fine as long as it is 15 gallons or more, a larger tank will be needed for a community.
  • Substrate Type: Any - Any A medium sized gravel works best.
  • Lighting Needs: Moderate - normal lighting
  • Temperature: 65.0 to 72.0° F (18.3 to 22.2° C) - Goldfish can tolerate colder temperatures, but this is the optimum range for activity and longevity in Goldfish.
  • Range ph: 6.0-8.0
  • Hardness Range: 5 - 19 dGH
  • Brackish: Sometimes - Goldfish are freshwater fish, but they have some tolerance for slightly brackish water. Any salinity for must be kept low, below 10%, a specific gravity of less than 1.002.
  • Water Movement: Moderate
  • Water Region: All - These fish will swim in all areas of the aquarium.

Social Behaviors

School of Common and Commet Goldfish, Carassius gibeliopreviously Carassius auratus auratus
School of Common and Commet Goldfish

Goldfish are very social animals and thrive in a community. Not only are they a great community fish but they are great scavengers as well. It is really not necessary to add other scavengers or other bottom feeders to the aquarium when you have goldfish.

Most fancy goldfish will thrive in both freshwater and tropical aquariums as long as there are no aggressive or territorial fish in the tank. Some good tank mates for fancy goldfish are the Chinese Blue Bitterling and the Northern Redbelly Dace.

Common Goldfish can be kept with other varieties of elongated goldfish, such as the Comet Goldfish and the Shubunkin, and they also do fine with Koi.

  • Venomous: No
  • Temperament: Peaceful - This fish is active and friendly.
  • Compatible with:
    • Same species - conspecifics: Yes
    • Peaceful fish (): Safe
    • Semi-Aggressive (): Threat
    • Aggressive (): Threat
    • Shrimps, Crabs, Snails: Safe - not aggressive
    • Plants: Threat - Goldfish produce more waste than most other freshwater fish and benefit greatly from more frequent water changes.

Sex: Sexual differences

Although is it impossible to sex Goldfish when they are young and not in breeding season, the male is usually smaller and more slender that the female. In the breeding season the male has white prickles, called breeding tubercles, on its gill covers and head. Seen from above the female will have a fatter appearance as she is carrying eggs.

Breeding / Reproduction

Common Goldfish are egg layers that spawn readily in the right conditions. See Breeding Freshwater Fish - Goldfish for more information on breeding Goldfish.

  • Ease of Breeding: Easy

Fish Diseases

Goldfish are subject to the same diseases as tropical fish. A couple of the more common problems are Ich, Swim Bladder Disease, and external parasites including flukes, lice and anchor worms. For more in-depth information about goldfish diseases and illnesses, see: Goldfish Care; Fancy Goldfish and Goldfish Diseases.

Availability

The Common Goldfish is readily available in fish stores and on-line, and is inexpensive

References

Author: Clarice Brough CFS, David Brough CFS
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Lastest Animal Stories on Common Goldfish


ron ash - 2014-11-27
I have a 7yr old gold fish in a 10 gal tank. He is about 8 inches, no other fish, keep tank clean, feed him large flake goldfish food. For the last ten days he has not be eating and is stuck on the bottom of the tank. I think this is a bladder problem and I have cleaned his tank and gave him peas but he does not eat. What more can I do?

  • Clarice Brough - 2014-12-02
    It's the eating habits of a goldfish that are the most common cause of swim bladder disease. Poor water quality can contribute, but the most common causes are such things as constipation from excess food, swallowing air, and feeding foods that ferment in the gut. Also, if food is withheld for too long, they loose gas in the gut so are unable to rise.

    So feed less... but more often, feed a variety, and feed consistently. Try offering sinking pellets instead of flakes and soak the food for a few moments before feeding, and the peas should also help.
Reply
Chloe - 2014-08-31
I have two fresh water fish living in a 96 litre tank with a Tetratec IN 800 filtration system, I preform 10-15% water changes every week and have just recently been bought two more fish, will the size of my tank be enough? The breed of fish are; Common goldfish, two Comet goldfish and a Shubunkin, I'll also be buying a gravel cleaner and an algae scraper very soon, the tank has just been set up and the two new fish are in the quarantine tank for a week or two, any help would be greatly appreciated, also, would a couple small snails be okay in the tank? I'm not buying them till I'm sure everything will be okay, thank you.

  • Clarice Brough - 2014-09-01
    No, unfortunately a 96 ltr tank is only 25 gallons, and will not be near enough water as these fish get older. When small it may work for awhile, but you will soon have to upgrade. As you can see in the aquarium setup info above, goldfish require a minimum of 10 gallons per fish. That is 50 gallons (190 ltr) just for the 5 goldfish.
Reply
Michelle - 2010-05-08
My daughter just won 5 common goldfish at a local carnival. Are they okay overnight (fish stores are closed), what size tank should we get, and are they okay until morning without a tank? The only options we have are a 1 gallon betta kit and a 10 gallon aquarium (we don't have the water or conditioner for the 10 gallon)?

  • Anonymous - 2014-06-03
    Ok, first of all you need more than a ten gallon tank. Number two, look on this website if you need help. It works wonders for me. thegoldfishtank.com
Reply
Jimmy Thai - 2010-07-29
Hi I have 8 hardy common goldfish, and they are juvenile fish. Can I keep them in a 10 gallon tank? Since they are still small. I know that they poop a lot and yeah I have to replace the cartridge every two weeks. Me and my dad are caring for the tank, later on we will buy a 60 gallon aquarium at the pet shop. How many gallons does one goldfish need? How big do these kind of goldfish grow? Do I have to build a pond? My tank has a hanging power filter. I wonder if needed an under gravel filter. I have colorful rocks and a bamboo, I know 8 goldfish need a lot of space so I don’t want them to live with lots of decorations. I’m the one who always cleans the filter. My dad always does the water change. Oh yeah, and I need to know how to clean out the fish tank, because my dad usually takes out all the water with a siphon, so I did some research and it said to siphon out 32 cups of water or 20% but I don’t know. So please tell me some steps. I feed my goldfish “Goldfish Flakes” , and that’s all. I tried feeding them “Goldfish Quick Grow Pellets” but when I threw some in, they ate it but then they spitted them out. I don’t know if they are the right age to eat them yet. What else can small goldfish eat? I don’t know if they can eat live food like water fleas or bloodworms. Please give me a good reply thanks!

  • Anonymous - 2014-06-03
    At lest one gallon per inch of goldfish.
Reply
LagoonPirate - 2011-08-27
I spent my early childhood on a floating logging camp in a large ocean and river fed lagoon. Most of the fish I saw as a kid were strange crosses between ocean and river fish. The next door neighbor raises koi, and gave me two large goldfish for my aquarium. One is about 7" long and one is about 5". I am going to experiment with compatible fishes, because in the wild, all fish are multi-type social. If they work out, that's OK. If they don't I would like to have somewhere I could send them to a good home. If anybody might take a fish off my hands if they are not compatible, I would be very happy. I will post them here when they are available. Thanks a lot for all the real great input.

  • Anonymous - 2011-08-29
    Awesome thoughts and sounds like interesting life.
Reply