Comet Goldfish – Comprehensive Care Guide to Pet The Fish

Comet Goldfish In Its Aquarium
By Garrison Hickles Updated

We all have heard a lot about this popular golden-shaded water species – Comet Goldfish because we know, it is one of the most common freshwater fish breeds that is loved by both beginner and experienced aquarists.

Now, you may ask, why Comet Goldfish is the most lovable breed for fish hobbyists than others? The answer is quite simple! Not all breeds have multiple good features and qualities at a time like color, shape, peaceful nature, and hardiness like this Goldfish. So, don’t you want to bring one to add ornamentation to your aquarium?

If you don’t know about its breeding and nourishment process then we are here to help you with a plethora of ideas on the care guide of Comet Goldfish, so that it becomes easy for you to take nourish your golden buddy.

Quick Details on Comet Goldfish

There are ample of things to know while taking care of your passive-natured friend but we have provided short and quick details about this fish to give you a brief knowledge.

Scientific Name Carassius auratus
Origin Freshwater of North America
Life-Span 4-14 years
Colors Golden, Red, White, Brown, Black, and Yellow
Temperament Peaceful
Size                Up to 12” (30 cm)
Diet Omnivore
Family Cyprinidae
Compatibility With Breeds of the Same Size and Some Other Variants of Goldfish
Tank Size 50 Gallon
Care Level Easy-Moderate


There are many other fish breeds that have same qualities but this fish can be an adornment to your aquarium that soothes the eyes of fishkeepers. You may also know this fish by other popular names like Single-Tail Goldfish and Koi (Black Comet Goldfish).

Not only in orange and yellow shades, but this breed is also found in other bright colors. However, keeping a fish in your aquarium is not your only responsibility, but you also have to take proper care of your pet Goldfish. If you nurture and nourish your pet Comet Goldfish properly then it can grow healthy up to 12” (30 cm) and can live up to 14 years old.


As per religious belief, Goldfish is the symbol of good luck according to Feng Shui. Moreover, medical practitioners also suggest keeping this bright fish in the bedroom of Alzheimer’s patient because the vibrant colors of this species can be eye-candy and help them release their anxiety.

Origin of Comet Goldfish

Native to the rivers and ponds near North America, Comet Goldfish was first found at the end of the 1800s. This fish became popular in the other parts of the U.S. later, and government staffs of America also started breeding this fish in the ponds of the U.S. Government Fish Commission and Washington D.C.

An American pioneer plus government employee of the U.S., Hugo Mulertt started breeding this Goldfish in the 19th century. The name was kept because of the comet-shaped long golden tail of the fish. Today, this breed is globally popular by this name, and fishkeepers like to pet this species in their commercial and residential places.

Comet Goldfish Appearance

As we have mentioned earlier, this fish got its name because of the elongated, slender and golden tail which exactly resembles a comet.

If you have noticed properly then you will find, Comet Goldfish has long flowing fins, but a common Goldfish has inflexible fins. Moreover, this fish is smaller in size than the common Goldfish.

The long heavy fork-shaped tail, single anal fin and slim body of Comet Goldfish make it different to other variants of the family. This fish has normal eyes and flat shinning scales in their body that spark light.

Along with orange, yellow and golden colors, you will find this species in other shades like white-red, brown, black and plain white. Also, the nacreous (cloud-like) pattern and coloration of some Comet Goldfish like Shubunkin Goldfish and other variants are quite attractive.


You can expect Comet Goldfish to grow up to 50% each week. In wild river this fish takes 3-4 years to reach its full size.

Temperament of Comet Goldfish

Most of the fish hobbyists prefer petting Comet Goldfish in their tank because of its adjustable and hardy nature. Moreover, you don’t require a huge tank for Comet Goldfish, a 50-gallon aquarium is enough to keep this medium-sized fish.

It is fun to watch this bright-colored fish swimming actively with the help of its long flowing fins and slender-shaped body. This fast-moving fish does not like an overcrowded tank because it likes to swim reckless and explore the surroundings of its home. So, keep the tank spacious by keeping fewer fish breeds with Comet Goldfish.

This familiar and intellectual fish can easily recognize its owners. So, it will be better if a single owner can feed Comet Goldfish because it can be aggressive if it is fed in the wrong way by some other person who is not familiar with the fish.

Suitable Tankmates for Comet Goldfish

Although it is a friendly and nonviolent breed, still, it cannot make good tankmates. It is not because of any territorial or less friendly behavior. Comet Goldfish has a tendency to eat lots of foods, so other tankmates can be at risk of malnourishment because of the scarcity of food.

Expert fishkeepers suggest keeping similar sized fish breeds with Comet Goldfish. Moreover, never over-crowd the tank of a Comet Goldfish, as we have mentioned above. Most suitable tankmates of Comet Goldfish are:

  • Rosy Barbs
  • Weather Loaches
  • Zebra Danios
  • Gold Barbs
  • Guppies
  • Dojo Loaches
  • White Cloud Mountain Minnows
  • Bristlenose Pleco

Unsuitable Tankmates

While setting a tank for Comet Goldfish, you need to be selective in choosing a companion for your golden-shaded buddy. Try to avoid keeping big, aggressive and too small fish breeds with Comet Goldfish. Some common species you should not house with this fish are:

  • Celestial Eye Goldfish
  • Bubble-Eye Goldfish
  • Snail
  • Shrimps
  • Oscar Fish
  • Green Terror
  • Flowerhorn


Comet Goldfish is an opportunistic feeder, so don’t keep this fish with crustaceans and invertebrates because it can end up by eating them.

Compatibility of Comet Goldfish

Comet Goldfish is comfortable to live with same size Goldfish. However, if you are planning to keep four of them together then purchase a 200-gallon aquarium so that the fish gets a huge space to swim.

Comet Goldfish may not feel happy to live with Telescope Eye Goldfish and Bubble-Eye Goldfish but it can be kept with some variants of the same size from the family of Goldfish such as:

  • Wakin Goldfish
  • Common Goldfish
  • Shubunkin Goldfish
  • Jikin Goldfish

Dietary Requirements for Comet Goldfish

Comet Goldfish consumes both meaty foods and vegetation in the wild including the waste products in the rivers and ponds. Fish nutritionists suggest providing plenty of fiber and nutritious foods to Comet Goldfish that will help it in growing more vibrant. Along with the natural foods Comet Goldfish is also comfortable in eating pellets or flakes.

For increasing brightness and the luster in the skin of Comet Goldfish feed some meaty foods to it such as:

  • Bloodworms
  • Small Insects
  • Brine Shrimp
  • Mosquito Larvae
  • Flies
  • Ants

You can also feed vegetables and herbs to Comet Goldfish as follows:

  • Mashed Peas
  • Cucumber Crumbs
  • Broccoli
  • Sliced Fruits like Strawberries and Blueberries
  • Lettuce Leaves
  • Carrots
  • Zucchini
  • Algae
  • Plant Roots

Put dry pellets and flakes that are specially made of fiber, carbohydrates and have other nutritional values such as:

  • Hikari Fancy Goldfish
  • Fluval Bug Bites
  • Tetra-Fin Balanced Bug Bites Goldfish
  • Repashy Super Gold – Goldfish and Koi Gel Food
  • Hikari Saki-Hikari Fancy Goldfish

Fishkeepers are confused with the quantity of food to be fed to Comet Goldfish because it has a tendency of eating much amount of food together. However, the wrong amount of food consumption or overfeeding may cause them Bloating and other digestive issues. So, try to feed them 2-3 times a day, and also remove the uneaten food from the tank and keep the water condition better.


Never keep the water temperature of the aquarium below 50°F because this fish may be affected by the digestive problem if they eat their food at cold.

Comet Goldfish Tank Requirements

As we have stated at the beginning that Comet Goldfish usually dwells in ponds, lakes, and rivers, so you need to maintain similar water temperature, condition and decoration to give a natural homely feeling to your pet Comet Goldfish. Here are some recommendations by experts which will be required while setting a Comet Goldfish tank:

Tank Size

Bring a 50-75 gallons rectangular tank to keep Comet Goldfish and you will need 200-gallon aquarium to keep a school of Goldfish because this active swimmer needs plenty of space to live and swim.


Comet Goldfish prefers dwelling in an eco-friendly environment surrounded by plants that helps them in hiding and taking rest. Therefore, try to keep some freshwater plants like Hornwort, Anacharis and Java Fern in the tank of your pet fish because aquatic plants will help in oxygenating the tank’s water.

You can also keep small gravels, stone chips and good substrate that is rich in mineral at the bottom of the fish tank. Moreover, keep some hiding caves in the aquarium because your pet fish needs a place for taking rest and hiding from predators of the tank.


Install a power filter in the fish tank to break the down the bacteria inside the aquarium and keep out the waste pollutants and chemicals from the aquarium. If the water of the fish tank is clean then your pet fish will get less affected with health issues that are caused because of poor hygiene.

You will get many aquarium filters in the market but experts recommend two names among them like Fluval C Power Filter and Aqua Clear – Fish Tank Filter.

Water Conditioner

If you install a water conditioner in an aquarium then it will help in cleaning and conditioning the water by killing the germs which cannot be seen through naked eyes but negatively affect your pet fish. Expert fishkeepers suggest to buy a quality water conditioner for your fish tank – Tetra AquaSafe Plus Water Conditioner/Dechlorinator to maintain the hygiene.


It will be better if you fix a moderate light at the ceiling of the fish tank because too much power may heat up the water of the aquarium which is not suitable for Comet Goldfish, the dweller of cold water. Turn the light about ten hours a day then switch it off at night, which may help in keeping the water temperature normal.

Water Type for Comet Goldfish

Managing the water temperature and range is the most important thing you should carefully follow. Water is the home of your pet Comet Goldfish, so don’t be careless while setting the tank. Follow some essential things mentioned below:


This freshwater fish is generally found from the cold water of lakes and rivers, so it cannot survive in warm water. The ideal temperature of a Comet Goldfish tank is 50-75°F (10-23°C). Moreover, this fish may not digest its food properly if it is kept at a warm temperature.

pH Level

The pH level of the water should be between 6.5-7.5.


The hardness of the water should be 5-19 dGH.

Cleaning Method

No need to remove the gravels and fish from the aquarium while cleaning tank water. You can use a gravel vacuum to clean the gravels in the tank.

While cleaning the objects, walls and corners of the fish tank, use a soft brush and liquid soap like API Goldfish Aquarium Cleaner. After washing, wipe out the entire tank and the objects with a soft cotton cloth. Maintaining the hygiene of the tank can help your pet fish live healthy and ailment-free.

Replacement Procedure

If you are changing the water of the tank weekly then you need to change 10% of water but if you change it once in a month then about 25-30% of water is needed to be changed. Always check the temperature, pH level and hardness of the water during the replacement process.


It is necessary to maintain the pH level of the water because if poor quality water with high acidity is kept in the tank of Comet Goldfish then its skin will start fading and its fins will adversely get affected.

Comet Goldfish Breeding

The breeding season of Comet Goldfish is spring when the water temperature is normal in river and pond. However, during the breeding process, keep the water temperature up to 58°F (14 °C) for the first month, and later increase its temperature up to 70°F (21°C) in a gradual process. Also, provide 12 hours light to the fish tank during that time. This will help in triggering the spawning behavior of the fish. 

You will find white prickles known as Breeding Tubercles on the head and gill covers of the male fish. The female fish will look fatter than the male with a round belly because it carries eggs.

Breeding of Comet Goldfish is not a very easy task because it requires a spacious tank and suitable water temperature during reproduction. This fish feels uncomfortable to lay eggs in captive, so experts suggest keeping them in a separate tank when the female fish is about to lay eggs.

The male Comet Goldfish chase the female and attempt to touch her stomach while laying eggs. The female fish can release up to 1000 eggs at a time nearby plants or in the aquarium caves.

Once after laying eggs, keep them in a separate tank because the parents can eat the eggs, and if you want to protect them then separate the fries from its parents during the fertilization process. The suitable temperature of the water should be 70°F (21°C) where you will keep the eggs. You can feed small brine shrimp to the school of newborn Comet Goldfish after hatching. Once they become mature, keep them back with their parents.

Types of Goldfish

Not only one, but there are multiple species in the family of Goldfish. All the variants have different colors, patterns, structure, and breeding process. You can keep any of them in your tank. Let us discuss a few common Goldfish, which can be kept in your aquarium.

  1. Common Goldfish – Both beginner and experienced fishkeepers can keep this peaceful golden-shaded fish in its tank. You will also find this fish in different colors like yellow and orange. It can grow up to 19” (48 cm). The bright color, single-rigid tail, bright eyes, and short fins are the specialty in the appearance of this fish.
  2. Shubunkin Goldfish – Shubunkin Goldfish is exclusive for its orange coloration and calico or black-spotted pattern. Along with black spots, you will also find other patterns like blue and white in the body of other Shubunkin Goldfish. Also, the shimmering scales and heart-shaped tail of the fish attracts the fish enthusiast.
  3. Wakin Goldfish – This double-tailed Goldfish has an elongated body and orange-white shades. Originated to the rivers near China, this twin-tailed fish is hardy and can adjust itself in any type of water. So, aquarists love to pet this breed.
  4. Ryukin Goldfish – This bright orange tall fish has a hump behind its head, and the scales of this species shines like silver. Its flowing tail is fan-shaped just like the Fantail Goldfish. This fish is quite hardy and it can survive in lower temperatures.
  5. Fantail Goldfish – The flowy tail of this fish exactly looks like a hand fan, so it is known as Fantail Goldfish. This European fish is a bit low swimmer, so it cannot adjust with active and aggressive breeds. So, try to keep similar types of fish in an aquarium with Fantail Goldfish.
  6. Pearlscale Goldfish – The round-shape of this fish is similar to a golf ball. Moreover, the scaling of the fish looks like shinning pearls fitted in the body of the fish. The appearance of this species attracts fishkeepers to keep them in an aquarium.       

Diseases of Comet Goldfish with Interventions

Comet Goldfish is a hardy breed but it is prone to some health issues which can be cured if you maintain the hygiene, food requirements and tank requirements of the fish. Get an idea about some common diseases of Comet Goldfish such as:

  • Swim Bladder Disease
  • Ich (Ichtyopthirius Multifiliis)
  • Fin/Tail Rot
  • Fish Lice
  • Bloating

Try to follow proper diet habit because Bloating and Swim Bladder disease is caused because of wrong nutrition given to the fish. Moreover, keep the water condition of the tank clean to prevent the fish from Ich, Fish Lice and Fin/Tail Rot.

Difficulties to Keep Comet Goldfish

Yes, Comet Goldfish is a peaceful and hardy fish, especially recommended to be kept in a beginner’s tank but it is not very easy to maintain the diet of the fish and breed the fish naturally.

Firstly, this Goldfish likes eating throughout the day whenever it gets food, which results in common health issues like bloating, obesity, and swims bladder disease. So, you need to make a proper diet routine for this fish and provide food timely in proper quantity. You have to check that neither the fish should suffer from malnutrition nor from overfeeding.

Secondly, it is quite difficult to breed a Comet Goldfish in captive because it only lays eggs in the spring season, and normal water temperature is needed to be maintained during the breeding process, as mentioned above. Moreover, you need a separate tank for the breeding process because the fish needs huge space for spawning and laying eggs. You also have to keep the eggs in a separate tank after birth because the parents can eat the eggs. If you are ready to accept these challenges then you can easily breed Comet Goldfish.

It is not only a hobby but it is a liability to look after the upbringing of your pet fish. Hope this complete care guide would help you in petting Comet Goldfish properly.

Interesting Facts about Comet Goldfish

  • Goldfish can see more colors than human beings.
  • Goldfish enjoys hearing music.
  • The taste buds of Goldfish are on its lips.
  • This fish is a symbol of luck and friendship in some Asian regions.
  • They eat their own poops.
  • Their teeth are in the back of their throat.
  • Goldfish don’t have the stomach, and they have an intestinal tract that helps the digestion process.
  • You will find most of the Goldfish in the White House instead of other aquarium species.

Know More about Other Freshwater Fish

Apart from Comet Goldfish, you may also love petting other freshwater fish. However, for breeding any kind of species, you need to know about its features, traits and care guide. You can brush your knowledge by reading a few articles of various fish as follows: