Comet Goldfish Care Guide – Feeding, Breeding & Tank Setup

comet goldfish

These beautiful aquatic creatures, also known as a comet-tailed goldfish from the cyprinidae family should look quite familiar to a lot of us. This is because they are one of the most common species of goldfish there are. Their distinguishing trait, and also what gave them their name is their beautiful tail fin. It resembles the tail of comets and even more so when they glide around in the tank.

One other trait that is amazing about the comet goldfish is they come in a wide variety of colors, which gives you more choices when deciding how to populate your aquarium. The species is actually a variant of the common goldfish, and was developed by a government worker in the 1880s, Hugo Melurtt, in the United States.

We can consider these fish native to the United States and is commonly found among pet stores. Their beautiful array of colors and playfulness is what gives them the award for one of the most popular species of fish for aquarists all around. Not to mention, it’s quite easy to care for these comets and they can survive in a pond or in an aquarium.

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Information ChartComet Goldfish
Care Level: Easy
Temperament: Playful and peaceful
Color: Yellow, red, white, brown, black
Lifespan: 4-14 years
Size: 12 inches (1 foot)
Family Cyprinidae
Diet: Omnivorous
Minimum Tank Size: 50 gallons
Temperature: 50-75 ºF, 10-24 ºC
Water Conditions: pH 6.5-7.5
Tank Mate Compatibility Other goldfish and koi

Comet Goldfish Care Level

As a developed species, the comet goldfish is quite easy to take care of. They do require some space as they are very active and playful and love to swim. They are quite fast as well, zipping back and forth around the tank. Comet goldfish are known to be much more active than other species of the cyprinidae family. They are hardy little fish that thrive well in outdoor settings.

Comet Goldfish Temperament and Behavior

As mentioned, the comet goldfish, which are native to the United States, are happy and active little fish. You can sit there all day and watch these little freshwater fish dashing quickly around the tank like little golden comets. They are also curious fish, and will spend a lot of their day just exploring the aquarium.

Adding new substrates and plants will keep your comets occupied for a while. Goldfish have been said to have short memories (hence the saying), but that doesn’t hold true for these goldfish. They can actually remember their owners and their way around the tank.

Other than adding new decorations in the tank, switching up the placement of plants and other decorations can keep them interested for a long time. Although these goldfish are happy-go-lucky creatures, they can get aggressive during feeding time. It would help to feed fish at opposite sides of the aquarium to reduce the chances of fights.

They don’t keep to any specific section of the tank either, as you will find your comet goldfish roaming the entire space, going on adventures.

comet goldfish

Comet Goldfish Appearance

Other than their golden color and other color variations, the comet goldfish are most well-known for their forked tail fin. This is what gives them their name, due to the resemblance to the tail of a comet. They are generally smaller and slimmer than the common goldfish as well and with only a single anal fin.

They also do not possess the bulging eyes, bellies and head that some goldfish species have.


How big do comet goldfish grow to? Surprisingly, comet goldfish aren’t the tiny little creatures you may be thinking of. If healthy and raised well, the comet goldfish can reach 12 inches (1 foot) long! Now that you know their size, you can only imagine the amount of space they need to live happily in captivity (but more on that later).

Comet goldfish grow quite quickly in their first few weeks but it will actually take 3-4 years for them to reach their full potential. This is why you shouldn’t find a permanent tank for them until you know them at their full capacity.


As mentioned before, comet goldfish can come in a variety of different colors. The golden comet fish is the most common (with hues ranging from yellow to red, but there are also more exotic colors as well.

The sarasa comet fish, are the comet goldfish that sort of look like koi fish with red and white markings. There are also white, brown, yellow and black comet fish. Sometimes they can even have cloud-like markings.


How long do comet goldfish live? You can expect your comet goldfish to keep you company anywhere from 4-14 years. The range is quite wide, and tank aquarium and water conditions as well as diet are the main factors that determine this. If you want these tropical fish to keep you company for a long time, then the right conditions are the keys. A goldfish lifespan is directly correlated with its environment.

Another issue they can encounter that will affect their lifespan in a large way is common diseases. However, this again can be remedied with the right conditions.

Feeding Comet Goldfish

Speaking of factors that affect the longevity of comets, our next section talks about their diet. Comet goldfish are what is known as omnivores, which means their diet can be meat or plant-based. We advise a healthy balance of the two for a healthy goldfish.

A lot of aquarists feed their comet goldfish pellets and flakes for their main source of nutrition, but we suggest supplementing that with healthy amounts of meat from sources such as insects and worms. You will know your goldfish is receiving a healthy diet due to its vivid coloring.

Healthy goldfish should have bright hues. You should also avoid overfeeding your fish, which is a big problem for a lot of people. To know the right amount to give to your fish, look at about how much they can consume in 2 min. Everything after that would be considered excess. It takes some practice and time to gauge exactly how much they need, and if they don’t consume all of it, just make sure you clean out the leftovers, especially if its meat.

They would also require a healthy source of vegetables as well. Some yummy greens that will help balance the goldfish diet would be bits of lettuce, broccoli, peas, carrots, cucumber, algae, and the list goes on. Sometimes giving them some berries such as strawberries will replenish their vitamins.

Goldfish should be fed the right amount about 2-3 times a day, any more than that would be overfeeding.


The comet goldfish are from the cyprinidae family, and originate from the United States and developed from the common goldfish.

Comet Goldfish Tank Conditions

Goldfish in general require cold water. They look tropical, but these freshwater fish need to be kept in a cool area in the house. Preferably, they shouldn’t call any place with direct access to sunlight home.


Do comet goldfish need a heater? No, in general, goldfish do not need a heater and the water temperature should be kept at around 50-75 degrees Fahrenheit (10-24 degrees Celsius). That is a big range and water temperature can also affect the weight and activity of the comet fish.

Water Conditions

As for the water conditions, the pH level should be fairly neutral and monitored and kept at 6.5-7.5. Depending on how many goldfish you plan to keep, you should have a pretty powerful filter. A lot of people like to fill their aquarium with multiple goldfish. You need to keep in mind that they do produce a significant bio-load and need powerful filters.

Looking for the filters that hang on the back of the tank could keep them out of the way of your active aquatic companions. Water changes should never be too drastic for any fish, but the comet fish are a little more forgiving. Although we would still suggest minimal alterations and water changes.

Minimum Tank Size

For comet goldfish, you are looking at a minimum size of a 50 gallon tank up to a 75 gallon tank. These freshwater fish will have the best life and live the longest in an outdoor pond or lake. Do not fall prey to the myth that goldfish can thrive in fish bowls. Since they can get up to 12 inches long, comets need sufficient space. Also due to their size, comet fish need large tanks up to 75 gallons or more if you plan on keeping more than one.

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Maintenance and Care

Comets are pretty hardy fish that can endure many conditions. They can put up with changes in the water and can live well in a lot of conditions. They don’t require much maintenance and water changing can happen every month or bimonthly.

Like much other fish, the comet goldfish is susceptible to Ich, or a fungus that grows on their scales. It’s easy to identify because the fungus is easily identifiable on the surface due to the white coloring. Comets are also prone to external parasites and bacterial infections. These are all treatable and can be prevented with the right conditions.

To see whether or not your comet fish are healthy, one thing to look at is their color. They should always be brightly colored and there should not be anything clinging to their scales. If you notice a loss in appetite among the fish, that is an indicator that they are not feeling well.

All in all, comets are tough fish that can handle a lot of chance as long as they are given a large space to swim (preferably a pond as opposed to a tank), and the right diet.

Suitable Tank Mates for Comet Goldfish

You would think these friendly comets would get along with just about anyone. While they possibly can temperamentally, that’s not what makes them bad roommates. The defining factor for them that makes them less than easy to live with is their unique needs.

For one thing, although these pond fish may seem like tropical fish, they are not. They live in freshwater, like most other tropical species but the temperatures they require are a lot cooler. For this reason, you cannot keep them together with fish that may be used to warmer waters.

While they are generally friendly fish, they may become aggressive during feeding time. And because of the fact that they are big eaters, they could consume all the food and leave nothing for their tank mates. This can be a problem in a community tank.

These two main reasons aside, there are other fish that comets can get along with, and that’s other goldfish and koi. The best thing to do when finding tankmates for your comet pond fish is to pair them with others from the same family.


Some of the more compatible species with your comet goldfish include rosy barbs, zebra danios, Oranda Goldfish and weather loaches.

Multiple comet goldfish can get along as well with one stipulation – the size of the tank. You are looking at about 50 gallons per goldfish, so you do the math at how large of a space they need. This is why we recommend a pond for these brightly-colored fish.

Breeding Comet Goldfish

Can comet goldfish have babies? Yes! Comet goldfish can surely breed and have babies, but they do need a large space for that. This is why raising them in a pond is the best. Some aquarists have tried to breed them in the tank environment but are unsuccessful due to the lack of space.

Since these goldfish are derived from the common goldfish, they can mate with them too. This is why if you plan on breeding them in the pond, you should remove all the other koi and goldfish and make sure that only comet goldfish are left in the pond. Otherwise, they may cross-breed and give you a whole other species altogether.

You won’t know what you will get so removing all other fish is the best method. Comet fish generally need colder waters but to trigger them into mating, you need to increase the temperatures by a few degrees. Although the process is simple, it may take a while. You would first need to keep them in a tank (since it’s easier compared to a pond) with their regular water temperatures and slowly increase it over time until it reaches about 22-24 degrees Celsius.

Once they are in the pond with warmer waters, they will do the deed. The increase in temperature is necessary to mimic the natural changes in the wild when seasons move from winter to spring. How do you know if you have succeeded? A large indicator would be if the male starts chasing the females around the tank in an attempt to mate. If successful, the female will release about 1000 eggs onto the plants in the pond.

It’s very important for you to find and remove all the eggs once they have been laid because they may become food for the parents. Scoop them up with a spawning mop and pop them into a tank for hatching. The water temperature in the aquarium should still be quite warm and the eggs should hatch within a week. We sure hope you have enough space planned for a whole new school of goldfish!


Is the comet goldfish the right one for you? The answer to this question can be reached if you have considered the following: space, variety, and food. They need a large space and hopefully an outdoor pond to really reach their full potential. This can reduce the chances of developing common diseases as well such as ich and swim bladder. If you have other fish, you can forget about keeping them in a community tank (unless you have other goldfish).

You would need to be ready with other accommodations if you plan on introducing come goldfish into your home. You would need to keep the water at a cooler temperature and to feed them the right food for a healthy diet.

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