Say hello to one of the most popular breeds of goldfish.
The Comet Goldfish has been with us since the late 1800s and has captivated fish enthusiasts ever since.
Its long forked tail and vibrant color are all good reasons why.
In this article we discuss everything you need to know about them including: how to care for them, expected size, dietary needs, known variations (such as the Sarasa Comet) and much more…
|Temperament:||Peaceful and Playful|
|Size:||Up to 12 inches|
|Minimum Tank Size:||50 Gallon|
|Tank Set-Up:||Freshwater, Cold, Planted|
|Compatibility:||Other goldfish varieties|
Comet Goldfish Overview
The Comet Goldfish, also known as Carassius auratus auratus, has been with us since the end of the 1800s. Hugo Mulertt is credited with the selective breeding program which led to the creation of this fish from wild Prussian Carps.
Since then it has taken the aquarium hobby by storm and this shows no signs of stopping.
They are well received in the hobby because of their hardiness and vibrant colors. A healthy Comet can live up to 14 years old and grow up to 12 in length.
They are traditionally orange/yellow but now due to selective breeding come in a variety of colors.
Comets are one of the more active breeds of Goldfish and are very fun to watch. They are fast swimmers and will spend lots of time exploring their surroundings.
Also, contrary to popular belief, they can remember their owners and their tank surroundings and decorations. For this reason you can switch up the decorations in your aquarium every couple of months to keep it interesting for them.
They can become aggressive during feeding, so to help ease this you can place feed at both sides of the tank to reduce competition for food.
Where To Buy Comet Goldfish
The Comet Goldfish got its name because of its long flowing golden tail which resembles a comet.
Whilst the common goldfish has ‘stiff’ fins, the Comet has long flowing ones; it is also smaller than ‘regular’ goldfish.
However the main way to differentiate between the two is the Comet’s long heavily forked tail; they have a slim body and only have a tail fin and a single anal fin.
Healthy versions will have normal eyes that are not bulging; their scales should also be flat and not bumpy. It should grow to 12 inches long when kept in a healthy condition.
They can come in a variety of colors with yellow/orange and orange/red being the more traditional colors. However you can also get them in:
- Red and White (Known as the Sarasa Comet)
- Black (technically these are a Koi/Comet hybrid)
You can also find them with nacreous (cloud like) coloration and patterning; however these are referred to as Shubunkin goldfish.
Comet Goldfish Habitat and Tank Conditions
You should remember that the Comet Goldfish you see in aquariums today were developed by Hugo Mullert in the 19thcentury.
This means that your Goldfish is a descendant of wild carps known as the Prussian Carp.
It’s therefore important that your aquarium matches the wild habitat of the Prussian Carp. These carp were native to Asia and lived in slow moving bodies of water such as rivers.
They could also be found in lakes, large ponds and ditches that were below the water level.
So how does this translate to your aquarium?
Well first of all in terms of whether to use a pond or tank; it really depends on the number of goldfish you’re getting. Generally if you want to keep more than 4 together, you’re going to need a pond (more on this later).
If you do get an aquarium be sure to get a long rectangular shaped one to provide them with plenty of space to swim in.
For substrate you can use small gravel. In terms of decoration and plants, plants are crucial to oxygenate the water. In addition they provide hiding places to help them feel safe and also act as food for your Comets, as they’ll occasionally nibble the plants. Anacharis, Hornwort and Java Fern all make ideal candidates.
The first thing to note here is that all goldfish require cold water. This means that you should keep your tank away from any heat sources and keep it in a cool room. If you place them in water that is too warm for them it can cause lifelong damage to their nerves.
You should be aiming to keep the water between 50-75°F; meaning that most places in the US will not need any additional heating and the tank will be kept at the right temperature through room temperature.
You should aim to keep the pH level between 6.5 and 7.5.
As for filtration you can’t really over-filter a tank with goldfish in; they produce a surprisingly amount of bio-load which can impact the condition of the water. You can use a hang-on-back filter or if you have the budget a canister filter would be better.
What Size Aquarium Do They Need?
First, you should know that the myth of goldfish only growing to the size of the tank is wrong and incredibly damaging to your fish.
Don’t be fooled by pet shops or anywhere else; it is not suitable to keep them in a small bowl.
They need at least a 50 gallon tank; we would recommend a 75 gallon tank.
How Many Comet Goldfish per Gallon?
As a minimum you should aim for at least 50 gallons per Comet Goldfish.
Comet Goldfish Tank Mates
Unfortunately they don’t make good tank mates, this isn’t because they are aggressive, and it’s due to these two main reasons:
- Although your Pond Comets live in freshwater, they are not tropical. This means you won’t be able to keep them with other popular freshwater fish, as the warm water is too hot for them.
- Second, they tend to consume lots of food, so other fish in the tank are at risk of being malnourished.
For this reason the bulk of options for other tank mates come in the form of other goldfish and koi. We would recommend keeping it simple and keeping them with similar sized varieties such as the Common, Shubunkin, Wakin and Jikin goldfish.
If you are looking to include other tankmates you can look at:
- Zebra Danios
- Bristlenose Plecos
- Weather Loaches
- Rosy Barbs
Remember though with any non-goldfish you will be playing a balancing act with the temperature of the tank.
Keeping Comet Goldfish Together
You can keep multiple Comet Goldfish together in a single tank but the biggest problem you’re going to have is size. As mentioned above each Comet needs at least 50 gallons, so if you’re planning on keeping 4 of them you’re going to need a huge 200 gallon tank.
Diet and Feeding
Remember above when we said that they are descendants of Prussian Carp. This means it’s important to understand what they eat in the wild so you can ensure your Comets are getting a wholesome diet.
In the wild Prussian Carp are omnivores; this means they eat both plant and animal matter. In their natural environment they will feed on plants, small insects, algae and anything else they can get hold of; however the majority of their diet is vegetation (this provides them with plenty of fiber).
Generally you can start by feeding your Comets goldfish pellets or flakes. These flakes are manufactured to meet their specific nutritional requirements; however this shouldn’t be their only food source.
If you want your fish to have bright coloration, a varied nutritious diet is crucial. For meat sources you can feed them:
- Small Insects
- Mosquito larvae
In terms of plants and vegetables you can feed them:
- Mashed Peas
- Fruit (Sliced Blueberries and Strawberries)
You will often see them munching away, and many keepers struggle with knowing how much to feed them.
You should aim to feed them 2-3 times a day and only give them what they can consume in less than 2 minutes. After this, you should remove the remaining food. One common illness with them (bloat) is caused by overfeeding so best to err on the side of caution.
Remember to keep their water temperature up above 50°F, because they will get digestive problems if eating when they are too cold.
Breeding Comet Goldfish
Unfortunately it is very difficult to breed them in an aquarium (it’s generally too small for them); instead they need a pond.
It’s also worth mentioning here that you should only keep Comet Goldfish in the pond. If you have other goldfish in there, they could cross breed and create different varieties.
To get them to start spawning they need a trigger. As they are cold-water fish the easiest way to do this is to increase the temperature in their tank/pond. You should keep them in cooler water (58°F) for at least a month and then gradually increase the water temperature until it reaches around 70°F; this will emulate the change in water temperature during spring in the wild.
You will know almost straight away if you’ve been successful as this will trigger spawning behavior. For the male he will chase the female around the pond and attempt to touch her stomach. If successful she will release her eggs (up to 1000 of them) into nearby plants.
We would recommend using a spawning mop; this way once the eggs have been laid you can remove them from the pond and place them in an aquarium. You want to remove the eggs otherwise the parents will eat them.
Leave the eggs in the new aquarium for around a week at 70°F and they will hatch. Within a few days they will start swimming and you will have a new School of Comet Goldfish fry.
Comet Goldfish FAQS
Comet Goldfish Growth Rate
During their first few weeks you can expect your Comet to grow up to 50% each week. It will take them around 3-4 years to reach their full size.
How Big Do Comet Goldfish Grow
They can grow up to 12 inches when fully matured.
Comet Goldfish Lifespan
You should expect them to live from 4 to 14 years. The wide lifespan accounts for the range of common illness which they can experience.
Common Health Problems
Like other Goldfish, the Comet is prone to some common health problems including:
- Goldfish Ich
- Fin Rot
- Fungal Infections
- Swim Bladder Disease
We will cover these common illnesses and the treatment of them in a future article.
Is the Comet Goldfish Suitable for your Aquarium? (Summary)
After reading this guide you should know if the Comet Goldfish is the right fish for your aquarium.
They add both a vibrant personality, and bright colors to your tank.
Just remember they will grow to become incredibly large, even though as a youth they can be only 2 inches in size.
Whilst they aren’t demanding to keep, they do require a large tank which generally means that they aren’t suitable for beginners.
Do you keep Comet Goldfish? Let us know your experience with them in the comments section below…